Structures with segments adapted to

Abstract

A wing designed to pass through a fluid medium is provided, the wing having a plurality of alternating protrusions and valleys along a trailing edge thereof. The described wing uses the plurality of protrusions and valleys to counteract noise that is a function of wind speed and chord length. In an alternative variant, instead of or in addition to cancelling noise, the plurality of protrusions and valleys are adapted to generate or correct noise such that the noise is generated in a desired frequency band. In this variation, the plurality of protrusions and valleys are configured such that the generated noise is in the desired frequency band based at least on a frequency band that repels various types of animals given a specified local wind speed. In another variation, the plurality of protrusions and valleys are adapted to improve the aerodynamic performance of the wings, whether in the context of separate use or with multiple wings working together within the system.

Description

[0001] Cross-references

[0002] This application is a non-provisional application filed November 23, 2022, entitled “Serrated Structure with Serrations Adapted to Transverse a Fluid Environment”, and filed April 6, 2023, entitled “Serrated Structure with Serrations Adapted to Transverse a Fluid Environment”, and claims all benefits thereof, including priority.

[0003] Both applications are incorporated into this paper in their entirety by reference. Technical Field

[0004] This application relates to an aerodynamic / aeroacoustic structure. The proposed structure is suitable for noise correction (e.g., reduction, alteration) during operation of the aerodynamic structure. The proposed aerodynamic structure can be modified onto or integrated into a wing to provide a series of protrusions and valleys. Background Technology

[0005] The wing and its associated aerodynamic characteristics are mechanical devices that can operate as generators, such as wind turbines; or transport devices, such as airplanes or drones; and structures for moving air, such as cooling fans.

[0006] An undesirable aspect of wing operation is the generation of undesirable noise. Noise arises as a result of the interaction between airflow and the physical wing components. Noise emissions from the rotor blades originate either from the tip (known as tip vortex noise) or from the trailing edge near but not at the tip.

[0007] It has been found that rotor blade noise is mainly composed of trailing edge noise, and there are two types: blunt trailing edge noise or "B-TE" noise, and turbulent boundary layer trailing edge noise or "TBL-TE" noise. Among them, TBL-TE is the biggest cause of rotor blade noise emissions.

[0008] TBL-TE is caused by the scattering of turbulent fluctuations within the boundary layer of the trailing edge blades, resulting in the radiation of broadband noise.

[0009] To reduce or correct noise emissions from the TBL-TE rotor blades, strengthening the rotor blade structure would be useful. Summary of the Invention

[0010] According to one aspect, an wing is provided having a plurality of alternating protrusions and valleys along its trailing edge, the wing being designed to pass through a fluid medium, the wing comprising an elongated body having a root end, a tip end, a pressure side, a suction side, a leading edge and a trailing edge separated by a chord length. The described wing uses the plurality of protrusions and valleys to cancel out noise (e.g., trailing edge noise), the noise being a function of wind speed and chord length.

[0011] In operation, the alternating peaks and valleys have specially adapted geometries suitable for noise correction (e.g., noise reduction). Geometries that can be established include axial spacing, distance between valleys, etc. The alternating peaks and valleys can be provided in the form of bimodal sawtooths, where the first and second peaks can have different heights. "Primary" valleys can be established between discrete sawtooths, and "secondary" valleys can be established between the first and second peaks (e.g., at the midpoint between the first and second peaks or any other point). Each of these peaks and its corresponding geometry can be adapted to provide improved sawtooths that induce noise correction at a target frequency or frequency band (which may also be affected by wind speeds at specific chord sections of the turbine).

[0012] The serrations supporting the protrusions and their valleys can be modified or otherwise attached to the trailing edge of a fluid-carrying body (such as a wind turbine blade). The specific geometry can be predefined based on the expected wind speed, the sound frequency to be corrected, etc. In some embodiments, the geometry can have limited passive shape-transformation capabilities, for example, by selecting a temperature-sensitive material. This is useful when temperature affects the wind speed and / or frequency of interest.

[0013] Compared to a solid / flat trailing edge, where all the air flowing below the wing mixes with all the air flowing above the wing at the same chordal position, the sawtooth pattern operates by dispersing the mixing of air over a larger area and preventing the turbulent properties of the mixture from occurring simultaneously at one location. This dissipates the energy difference between the two flows over a larger time span, thus lowering the threshold for turbulent sound formation.

[0014] By means of the proposed method, some air will mix in the valleys. If the distance d' between these valleys is equal to half the wavelength of the sound, the noise at that wavelength will undergo destructive interference, and the noise at adjacent wavelengths will undergo a gradual decrease in intensity equal to that at an interval of a parabolic relationship, thus having the technical effect of correcting (e.g., reducing) the overall sound production.

[0015] In some embodiments, noise at a specific wavelength is not attenuated, but rather converted to different frequencies that are less harmful / undesirably less harmful, or that may be converted to useful frequencies (e.g., for animal deterrence). Reducing w' or w” within the constraints of practical limitations in production and use can have beneficial technical effects in allowing for more destructive interference and targeting more frequencies of interest. Variations in d” can affect the reduction of vortex by allowing air to mix at alternating axial positions. This can further reduce noise spikes and affect aspects of the tone of the emitted noise.

[0016] Allowing air to mix at different axial positions behind the rotor blades can be advantageous because it reduces swirl formation, which in turn improves the turbine wake by increasing mixing and reducing drag. Swirl formation can negatively impact aerodynamics and lowers the threshold for swirl formation by shifting the peaks at different axial positions. That is, less energy is required for swirl formation when the axial positions are spaced apart over a longer time-space period. This is a characteristic of time-dependent energy transfer, a physical phenomenon described for the first time by the inventors.

[0017] d” represents the height difference between the two peaks. Variations in d” result in one peak being higher than the other, creating different axial positions for air mixing. For example, d” can be measured as the height of the left peak minus the height of the right peak, where a positive value indicates the left peak is higher, and a negative value indicates the right peak is higher. As described, different axial positions affect vortices because there are alternating axial positions in the flow. These influence noise spikes and aspects of noise tone by shifting sound from one frequency to another. Specifically, shifting lower-frequency noise to higher-frequency noise may be desirable because the noise travels a shorter distance from the turbine, or attenuates faster in the atmosphere than lower-frequency noise (e.g., with shorter wavelengths). Different versions of d” configurations are considered.

[0018] In the first embodiment, each d” has the same orientation, meaning that either the left or right peak is always higher than the other peak. In the second embodiment, each d” may have opposite orientations, meaning that the sawtooth pattern alternates between higher left and right peaks. For example, in the first embodiment, d” is always positive or negative. In the second embodiment, d” alternates between positive and negative values ​​(e.g., higher on the left, then higher on the right, and so on).

[0019] The d” value or configuration can be constant across the serrations, or in some embodiments, it can continuously vary based on results identified at specific points along the blade, for example, the distance from the hub. In another variation, separate segments exist, each with a different d” value or configuration. This variation is easier to manufacture but less targeted compared to the continuously varying version for each serration, though both can be used to improve the noise characteristics of turbine blades.

[0020] Finally, each segment can also have a different configuration, and this can depend on the type of fluid flow experienced at each segment. The value / configuration of d” can be determined based on a combination of contributing factors from d’, w’, and w”, as each of these contributing factors may contribute to the overall noise tuning characteristics of the sawtooth. For example, d’, d”, w’, and w” can all be selected together to match the overall noise correction of the turbine or the turbine airport as a whole with the desired result, recognizing that the selection of d’, d”, w’, and w” may also have other effects on lift, drag, weight, or other operation-related aerodynamic factors. For example, d” can be selected or configured to attempt to convert undesirable sounds into frequencies that might deter animals.

[0021] In another embodiment, the value of d” is based on its local radial position, and therefore on the local flow velocity of the turbine given RPM and TSR. Given a particular d”, this, combined with atmospheric effects such as air density, temperature, and humidity, can affect the performance of the sawtooth.

[0022] As described in the proposed embodiments, reducing trailing-edge turbulence and boundary layer aerodynamic effects can have beneficial effects on turbine fatigue and extreme loads, thereby improving asset operation and lifespan. This can help create enhanced performance modes (LO modes) focused on load optimization and improve the asset's power performance. Load reduction is also a substantial step in creating new turbines that meet type-level requirements, meaning that a new generation of turbines can be developed that take into account the beneficial load reduction potential of the proposed embodiments. Wind asset operators can similarly leverage the benefits of load and vibration reduction, as reduced maintenance equates to increased uptime and revenue.

[0023] Numerous strategic opportunities can be gained by modifying the sound / noise generated by the rotor blades, and thus potentially modifying the turbine or the entire turbine field. The turbine can be coupled to a controller to modify operating characteristics such as angle of attack and rotational speed, allowing the turbine to operate more aggressively as long as it does not exceed a sound threshold. In this example, the controller may include feedback control circuitry that takes the sound measured by a sensor as input and uses it to control / optimize power generation. The sensor may be positioned on the turbine itself or as a microphone positioned at a distance from the turbine, and the measurement results are relayed back to the turbine.

[0024] In another variation, the turbine can be located closer to human settlements (e.g., according to standards / noise regulations) because noise at certain unpleasant frequencies can be reduced. This is especially useful if lower frequencies are attenuated, as lower-frequency noise travels further. In yet another variation, the density of turbine field can be increased (e.g., as long as the overall noise contribution does not exceed a certain threshold) because noise at relevant frequencies can be reduced. Therefore, the sawtooth and corresponding methods proposed in this paper can be useful in many different practical situations.

[0025] In an alternative variation, instead of noise cancellation or in addition to noise cancellation, the plurality of protrusions and valleys are adapted to generate or modify noise such that the noise is produced in a desired frequency band. In this variation, the plurality of protrusions and valleys are characterized by generating noise in a desired frequency band, which is at least based on a frequency band that repels various types of animals (e.g., birds, bats, fish, insects) at a given specified local wind speed (e.g., a high-frequency band outside the range of human hearing). To generate sound (e.g., noise) in the desired frequency band, a portion of the structure or the blade itself may include one or more pores, such as holes. Depending on their configuration, multiple pores may operate together to generate noise at multiple different frequencies (e.g., similar to "Swiss cheese"), and for example, the pores may be of different sizes, such as 0.5 mm, 0.6 mm, 0.7 mm, etc.

[0026] The orifice operates by creating a pressure difference between the suction and pressure sides, for example, generating a whistling sound based on its size through resonance at a frequency derived from the pressure difference. Depending on the desired sound output, the orifice can be a straight circular orifice or an elliptical orifice. The orifice size can be set as a function of the local wind speed and the desired sound frequency output.

[0027] The size of the aperture can be adjusted based on the desired noise level. Depending on the location where the impact occurs or is expected to occur, one or more apertures can be positioned in various different sections, and for example, in areas where the highest airspeed is encountered (and therefore the impact force on animals is most dangerous—even without direct impact, animals can be injured by rapid pressure changes / turbulence), they can be positioned on the distal portion near the tip of the blade or rotor. In some embodiments, the size and / or geometry of the aperture can be dynamically determined and reset during operation by changing the aperture size or geometry. For example, a small aperture motor can be used to change the aperture size, enlarging or shrinking the aperture as needed. A single motor can be coupled to each aperture, or in some embodiments, a set of general-purpose motors can be used across multiple apertures. Similarly, if a protrusion can be modified with a motor to change its variable geometry, similarly, a motor driving the protrusion change can also be used to change the aperture size. In a particular embodiment, each protrusion section has a corresponding set of one or more motors that control the operation of said particular section (manually set or in conjunction with sensors measuring operating characteristics such as local wind speed, blade geometry / profile, or boundary conditions).

[0028] From a modification or attachment perspective, pores can be embedded into protrusions, allowing the protrusions to interoperate together to provide beneficial sound (high-frequency animal repulsion noise) and reduce noise within the human audible range through destructive interference or changes in the aerodynamic profile. Combined approaches are useful as single modification / profile corrections and have a dual function in altering the overall sound / noise profile emitted by the device during operation.

[0029] Therefore, in this approach, the aperture is manipulated to generate sound to deter / repel animals. If the aperture is positioned on the distal portion of the rotor or blade, it creates a “gap zone” established in the ring during turbine operation, and this helps create a “noisy” area for animals to identify and avoid (e.g., this would not be a good “habitation site”), which helps mitigate some of the potential environmental challenges associated with actual operation (e.g., reducing bat mortality may be important for farmers).

[0030] In some embodiments, it may be necessary to protect, for example, specific species of bats. Since different bat species are known to use different frequency bands and fly at different wind speeds, a specified atmospheric wind speed determined by turbine SCADA data and the relevant effective local wind speed on the turbine blades (determined by the controller via RPM) can be used to inform the exact geometry of the aperture, and the protrusions or valleys are adapted to match these criteria to target the desired frequency band during manufacturing. In an alternative embodiment, the protrusions or valleys are adapted during operation by adaptive control based on dynamically or periodically determined local wind speeds and / or other operating parameters of the turbine. Because different parts of the blade or wing may experience different local wind speeds, protrusions or valleys in different areas can have different geometries (discretely or continuously) so that the same or approximately the same noise frequency can be specifically generated. In an alternative embodiment, the geometry used to generate a specific frequency can be an aperture, hole, slit, rounded corner, recess, ramp, etc.

[0031] In one embodiment, the alternating geometry of the protrusions and valleys positions two adjacent valleys relative to each other at different axial distances in the chordal direction, such that each valley can emit sound waves in a known frequency range, which deconstructively cancel themselves out when interacting with near-sound waves generated by adjacent valleys (e.g., through destructive interference).

[0032] For example, to target a specific frequency, serrations of different lengths can be created across the span of the wing blade, and the different lengths can be based on a portion of the blade or on the continuously changing profile of the blade.

[0033] Partial approaches can be used to curb manufacturing complexity, as generating unique serrations across the entire span of a blade can be more challenging. Therefore, in this variation, the method may include establishing multiple (e.g., 2, 3, 4, 5, 6, 7, 8, 9, 10) lengths, rather than continuously varying the lengths, which will be effective for different sections of the blade.

[0034] Wind tunnel testing was used to experiment on the example prototype wing, demonstrating noise reduction across multiple frequencies, with a significant reduction in a specific frequency range of the audible spectrum.

[0035] According to another embodiment, given the operating temperature, boundary displacement thickness (δBL), and total local wind speed (UL), the axial spacing between two adjacent valleys (e.g., the exact or approximate axial spacing) is controlled by the input parameter of sound speed (Us). As mentioned above, the peak frequency of the trailing edge noise is a function of wind speed and chord length.

[0036] In contrast to Chong, the method proposed in this paper targets a different geometry and chord relationship. In the proposed method, the chord relationship d' is adapted to be based at least on sound velocity, boundary displacement thickness, and total local wind speed.

[0037] In a particular, non-limiting instance, in one embodiment proposed herein, the local spatial dependency chord relation d' between the two valleys is given by the following equation:

[0038]

[0039] Its d' = distance between valleys, Us = speed of sound, δ BL = Boundary displacement thickness, and U L = Total local wind speed.

[0040] In the proposed method of this embodiment, the chord relationship d' is based on specific input parameters of a given operating temperature, boundary displacement thickness (δBL), and the sound velocity (Us) of the total local wind speed (UL). Since different zones of the structure (e.g., blades) may encounter different local wind speeds, as further described, variations are possible where different zones of the structure have different d's, and these zones can be established along the structure on a discrete basis or approximated on a continuous basis (e.g., determining the value of d' for each sawtooth based on the prevailing local wind speed at a specific sawtooth).

[0041] In an alternative variant, multiple protrusions and valleys, in addition to noise reduction, are adapted to improve the aerodynamic performance of the wing to which they are applied. Aerodynamic performance is measured as the ratio of lift to drag of the wing and by the mass of the wake behind the wing.

[0042] In one embodiment, the wing is a rotor blade of a wind turbine. The structure described herein is designed to reduce the scattering of turbulent fluctuations within the boundary layer at the trailing edge of the rotor blade. As a result, rotor blade protrusions and valleys for wind turbines are provided, which, through their application and use, reduce noise emissions and / or improve the efficiency of the wind turbine as a whole.

[0043] In one embodiment, given a finite noise power level, the structure described herein can improve the efficiency of a wind turbine by allowing for a larger rotor RPM. Such use is desirable for wind turbine operators as it allows for the generation of more power without exceeding ambient noise guidelines.

[0044] According to one aspect, alternating protrusions and valleys of the rotor blades are applied over a range of 40-96%, with the root of the rotor blade representing 0% and the tip of the blade representing 100%.

[0045] In another embodiment, the wing is the rotor of the drone. The structure described herein is inherently modular and adaptable, so any wing and its associated input parameters will affect its geometry and use.

[0046] According to one approach, alternating protrusions and valleys are applied within the 0-99% range of the rotor, where the root of the rotor represents 0% and the tip represents 100%.

[0047] On the other hand, the alternating protrusions and valleys of the rotor blades can alternate in length and width, and their distribution is uneven.

[0048] On the other hand, relative to the orientation toward the blade tip, the length, width, and relative distance between the alternating protrusions and valleys of the rotor blades are generally reduced.

[0049] On the other hand, the alternating ridges and valleys contain geometric cuts and splines so that the airflow does not interfere with the path of least air resistance as it moves from the leading edge to the trailing edge of the wing.

[0050] According to another perspective, alternating protrusions and valleys can be composed of biological or non-biological materials.

[0051] On the other hand, its manufacturing method can be through injection molding, 3D printing, or laser or waterjet cutting.

[0052] According to another embodiment of the invention, the alternating protrusions and valleys may be flexible or rigid and / or have a curved or linear structure.

[0053] According to another embodiment of the invention, the leading edge of the attachment surface of the alternating protrusions and valleys may have a curved or linear structure.

[0054] According to another embodiment of the invention, the alternating protrusions and valleys of the rotor blades and the aerodynamic body can be an integral structure.

[0055] According to one aspect, the alternating protrusions and valleys, as well as the aerodynamic body of the rotor blades, can be two (2) or more components connected to each other by adhesive.

[0056] According to one aspect, the alternating protrusions and valleys and the aerodynamic body of the rotor blades can be two (2) or more components connected to each other by clamps or multifaceted structures that adhere the base sections of the alternating protrusions and valleys to the suction side and / or pressure side of the wing.

[0057] According to another embodiment of the invention, various methods for applying alternating protrusions and valleys to the body of an aerodynamic rotor blade can be performed, and these various methods can be applied to existing wind turbines and / or wind turbines during manufacturing.

[0058] According to another embodiment, the structure can be applied to a non-limiting example wing without relying on its aerodynamic design. Similar types of noise emissions may also originate from the trailing edge of the rotor on a drone, where a typical 'buzzing' sound can be heard by nearby individuals. For drone operators, whether for civilian or military purposes, it is desirable to reduce noise spikes during drone operation.

[0059] The methods proposed in this paper can be used to improve the feasibility of green technologies, such as renewable energy structures and their modifications. Specifically, these technologies are suitable for modifying or otherwise altering operational aspects, for example, improving efficiency and / or reducing harmful impacts.

[0060] Given environmental and climate purposes and objectives, renewable energy projects are desirable as technological solutions to challenges related to future sustainability. The adoption of these technologies is still in its early stages of development, and improvements could help accelerate adoption compared to other forms of energy production.

[0061] Therefore, an innovative approach based on bionics and its related aerodynamics is proposed. Attached Figure Description

[0062] The accompanying drawings illustrate embodiments by way of example. It should be clearly understood that the descriptions and drawings are for illustrative purposes only and are intended to aid in understanding.

[0063] Embodiments will now be described by way of example only with reference to the accompanying drawings, in which:

[0064] Figure 1 This is a side front view of a horizontal axis wind turbine based on existing technology.

[0065] Figure 2 yes Figure 1 The image shows a side perspective view of one of the blades in a horizontal axis wind turbine.

[0066] Figure 3A According to some embodiments Figure 1 A front view of the blade and the structure modified onto the blade.

[0067] Figure 3B It is a modification based on some embodiments to, for example Figure 3A An enlarged front view of the structure on the blade shown.

[0068] Figure 3C According to some embodiments Figure 1 A front view of the blade and the alternative structure modified onto the blade.

[0069] Figure 3D It is a modification based on some embodiments to, for example Figure 3C An enlarged front view of the alternative structure on the blade shown.

[0070] Figure 4 According to some embodiments Figure 3A Side perspective view of a section of the structure shown.

[0071] Figure 5 According to some embodiments Figure 4 The front view of a section of the structure shown.

[0072] Figure 6 It is a two-dimensional diagram showing the composition of... Figure 3A The blades shown have a structure and do not have Figure 3A The sound level produced by the blades of the structure shown is a function of frequency.

[0073] Figure 7A According to some embodiments Figure 5 Side perspective view of a section of the structure shown.

[0074] Figure 7B It is included according to some embodiments Figure 7A A side view of one of the protrusions in the section of the structure shown.

[0075] Figure 7C According to some embodiments Figure 5 A top perspective view of a portion of the structure shown.

[0076] Figure 7D A cross-sectional perspective view of the example valley geometry is shown.

[0077] Figure 8A , 8B And 8C are respectively Figure 5 The side view of the section shown connects to the pressure side of the blade, the suction side of the blade, and both the pressure side and suction side of the blade. Figure 2 The trailing edge of the blade shown.

[0078] Figure 8D yes Figure 5 The side view of the section shown, which is connected to Figure 2 The trailing edge of the leaf shown defines the basal segments and structures of the primary and secondary valleys, which can be at relative angles to each other.

[0079] Figure 9This is a view of variations of noise generated for deterrence according to some embodiments.

[0080] Figure 10 This is an example wing / wing shape for reference. Detailed Implementation

[0081] As described in the various embodiments herein, methods suitable for improving the adoption and feasibility of different types of wing structures are presented by correcting the noise generated by the wing structure as it moves through a fluid (such as air or water).

[0082] Specifically, a particular structural approach is proposed that utilizes geometric features to modify various aspects of aerodynamics during fluid-structure interaction. These geometric features are used to reduce noise at target frequencies, subsequently influencing aeroacoustics in a desired manner. For example, unwanted noise at target frequencies in the human hearing spectrum can be reduced, while alternatively or simultaneously, in various variant embodiments, desired noise at the target frequencies can be generated (e.g., to repel animals, making them more likely to avoid the wing or control surfaces, and thus preventing unintentional impact from the wing). Variations are also proposed, thereby providing modifications or new wing structures to existing wings, for example, which can be used as rotors of propellers, turbine blades, or aircraft wings (e.g., airplanes, drones).

[0083] As described in this paper, many different variations can be achieved by using different cross-sectional geometries, varying widths between protrusions, and different valley / protrusion geometries. These geometries are adapted based on desired noise frequency corrections and, in some cases, can be done during the initial manufacturing phase or added through modifications to existing wings (e.g., blades).

[0084] Specifically, the geometry is connected to the trailing edge of the wing, and the applicant has been experimenting with and proposing various methods to reduce trailing edge noise. For example, in U.S. Patent No. US10690110B2 of 2014 / 2015 (also published as Church's US20170276117A1, and corresponding Canadian, European, and PCT applications), the applicant proposed an alternating protrusion method having two sets of protrusions of length adapted to establish destructive interference for or at least based on a target sound frequency. According to embodiments, these protrusions can extend from either the trailing or leading edge.

[0085] Numerous variations have been developed, including rigid protrusions with different types of profiles, such as bulbous protrusions. In this approach, the length of adjacent protrusions varies based on the wavelength of the sound waves generated at different regions of the rotor blade, the wavelength of which is based on the velocity of the fluid interacting with it at different points. Variations and improvements to earlier methods are proposed as described in this specification.

[0086] Herr et al.'s U.S. Patent Application Publication No. US2008 / 0166241 discloses a method for reducing rotor blade noise emissions during operation by employing bristles at the trailing edge of the rotor blade. According to Herr, shorter bristles achieve better reduction results at lower frequencies, while longer bristles tend to be more effective at higher frequencies to reduce trailing edge-related noise. Herr explains that a combination of bristles with significantly different external dimensions within the same region of the blade contributes to achieving more efficient reduction characteristics over a wide frequency spectrum. Radiated noise from the rotor blade is greatest for incident pressure waves aligned with and propagating perpendicular to the edge of the rotor blade. As the pressure wave passes the edge, it encounters a sudden change in acoustic impedance, causing noise scattering. The bristles can be considered a means of distributing this sudden change in impedance over a finite distance, thereby reducing the intensity of the scattering process.

[0087] However, in Herr, straight sawtooth also causes a significant increase in noise at high frequencies (>2000Hz). Using straight sawtooth requires careful placement and careful consideration of width and length to achieve the desired effect. Additionally, turbulent inflow noise can affect the noise spectrum of the wind turbine at low frequencies. Therefore, in Herr, both the inflow and outflow airflow must be managed to achieve the desired effect, which is technically challenging.

[0088] To improve the effectiveness of saw teeth, some other methods apply structures between the saw teeth to reduce noise. For example, PCT application EP2016 / 058428 describes a saw tooth with a porous material between two teeth.

[0089] Others claim to have drawn inspiration from owl wings, seemingly without fully understanding the mechanisms behind their movements. Chong et al.'s PCT application GB2020 / 051178 describes the use of a series of alternating rigid protrusions, where valley-to-valley and valley-to-peak distances are combined when forming the serrated geometry. In Chong et al.'s U.S. Patent Application Publication No. US20220074383A1, a method for adding wing components using slit forming and double trailing edge serrations is proposed.

[0090] The "double-root" structure proposed by Chong includes two axial heights, in Chong's Figure 1 A is marked as h' and h", and a specific geometric relationship is defined as follows: in The convective velocity factor has a value of 0.4 to 0.8, and the relationship between h' and h” satisfies the empirical factor: U ∞ It is the free-flow velocity, measured in m / s.

[0091] As Chong points out in paragraph 0098, the structure proposed by Chong must satisfy the Strouhal number condition, and specific empirical factors explain the possible inequalities between h' and h” in the frequency scaling.

[0092] In Chong, especially in paragraph 0100, h' is adjusted accordingly to affect, for example, the maximum noise reduction peak.

[0093] This paper proposes an improved method and structure that uses alternating protrusions and valleys, which in operation have specially adapted geometries suitable for noise correction (e.g., noise reduction).

[0094] The geometry that can be established can have axial spacing, distances between valleys, etc. Alternating ridges and valleys can be provided in the form of bimodal sawtooth, where the first and second peaks can have different heights. "Primary" valleys can be established between discrete sawtooths, and "secondary valleys" can be established between the first and second peaks (e.g., at the midpoint between the first and second peaks or any other point). Each of these peaks and its corresponding geometry can be adapted to provide improved sawtooth, which induces noise correction at the target frequency or target frequency band (this may also be affected by wind speeds at specific chord sections of the turbine).

[0095] The serrations supporting the protrusions and their valleys can be modified or otherwise attached to the trailing edge of a fluid-carrying body (such as a wind turbine blade). The specific geometry can be predefined based on the expected wind speed, the sound frequency to be corrected, etc. In some embodiments, the geometry can have limited passive shape-transformation capabilities, for example, by selecting a temperature-sensitive material. This is useful when temperature affects the wind speed and / or frequency of interest.

[0096] Numerous strategic opportunities can be gained by modifying the sound / noise generated by the rotor blades, and thus potentially modifying the turbine or the entire turbine field. The turbine can be coupled to a controller to modify operating characteristics such as angle of attack and rotational speed, allowing the turbine to operate more aggressively as long as it does not exceed a sound threshold. In this example, the controller may include feedback control circuitry that takes the sound measured by a sensor as input and uses it to control / optimize power generation. The sensor may be positioned on the turbine itself or as a microphone positioned at a distance from the turbine, and the measurement results are relayed back to the turbine.

[0097] In another variation, the turbine can be located closer to human settlements (e.g., according to standards / noise regulations) because noise at certain unpleasant frequencies can be reduced. This is especially useful if lower frequencies are attenuated, as lower-frequency noise travels further. In yet another variation, the density of turbine field can be increased (e.g., as long as the overall noise contribution does not exceed a certain threshold) because noise at relevant frequencies can be reduced. Therefore, the sawtooth and corresponding methods proposed in this paper can be useful in many different practical situations.

[0098] In actual experiments, according to one embodiment as described herein, and compared with the same turbine having triangular serrations according to an alternative method, a modern commercial multi-megawatt wind turbine is equipped with six (6) serrated segments 200A, 200B, 200C, 200D, 200E, and 200F. The geometry of segment 200A is given by 335 mm d', 12 mm d”, 33 mm w', and 33 mm w”. The geometry of segment 200B is given by 305 mm d', 11 mm d”, 30 mm w', and 30 mm w”. The geometry of segment 200C is given by 260 mm d', 10 mm d”, 24 mm w', and 24 mm w”. The geometry of segment 200D is given by 225 mm d', 8 mm d”, 20 mm w', and 20 mm w”. The geometry of section 200E is given by 220mm d', 7mm d”, 18mm w', and 18mm w”. The geometry of section 200F is given by 150mm d', 5mm d”, 10mm w', and 10mm w”.

[0099] Variations of this geometry are also possible, such as the following: Section 200A has a geometry of 350mm d', 13mm d”, 15mm w', and 15mm w”. Section 200B has a geometry of 325mm d', 12mm d”, 13mm w', and 13mm w”. Section 200C has a geometry of 300mm d', 10mm d”, 11mm w', and 11mm w”. Section 200D has a geometry of 275mm d', 8mm d”, 8mm w', and 8mm w”. Section 200E has a geometry of 225mm d', 7mm d”, 7mm w', and 7mm w”. Section 200F has a geometry of 175mm d', 5mm d”, 5mm w', and 5mm w”. Such variants would improve noise reduction and production at the expense of reducing practical considerations such as increased material, handling, and production vulnerability and load, although either scenario is possible based on expertise in turbine operation, manufacturing, and installation.

[0100] These geometries are shown in the examples and are provided as examples, non-limiting illustrative embodiments.

[0101] Referring to Table 1, when analyzed according to IEC standards, putting the results of such tests of the proposed embodiments into practice shows a significant reduction in apparent sound power level (SPL). Δ in the table refers to the difference (improvement) and is provided as an absolute value.

[0102] The experiment was conducted on a wind turbine encountering wind speeds of 8 m / s (as measured at the hub), but other variations are possible, such as 4 m / s, 10 m / s, etc. The wind speed measured at the hub is a useful notation because it represents the location of the maximum load on the wind turbine.

[0103] Table 1

[0104] 8m / s of wheel hub f Δ noise reduction Hz dB 10 3.8 12.5 3.5 16 3.7 20 3.1 25 3.4 31.5 3.2 40 2.9 50 2.8 63 3.1 80 3.1 100 2.6 125 1.9 160 4.1 200 3.4 250 3.4 315 3.7 400 2.8 500 2.7 630 2.4 800 1.3 1000 0.4 1250 0.3 1600 1.3 2000 1.7

[0105] Because low frequencies travel farther in the atmosphere than high frequencies, attention needs to be paid to the frequency range below 2000 Hz, which is considered the most audible. For example, the 630 Hz band travels an order of magnitude farther in the atmosphere than the band below 800 Hz. Therefore, the low-frequency band at 630 Hz is an order of magnitude more important in terms of audibility than the adjacent band at 800 Hz. Therefore, the geometry of the proposed embodiment is fine-tuned to reduce these frequency ranges and to give greater emphasis to the gradually decreasing frequency bands. This fine-tuning is achieved by modifying d', whereby in this example, the secondary valley 231 can be moved closer to the primary valley 233, which will reduce d'. This will be used for higher frequencies with reduced wavelengths at the same nominal radial position. Fine-tuning may include modifying (e.g., increasing) the tip speed ratio by control updates to optimize the torque requirements of the controller. The TSR (tip speed ratio) can be increased by control updates to optimize the torque requirements of the controller.

[0106] The signature 'whoosh' sound of wind turbines is due to low-frequency sound waves below 2000 Hz. In analyzing the results, a 2.6 dB(A) variation in the maximum broadband noise level was found in the control mode studied. This is significant because turbines are certified based on the generated maximum broadband noise level and hub height, where 104–107 dB is common. Reducing the generated maximum broadband noise allows turbines to be positioned closer to residential areas, thus enabling more efficient use of land in wind farm development. In practice, reducing the maximum broadband noise helps mitigate the risk of power generation cuts and the economic penalties associated with excessive noise emissions.

[0107] These are determined by local laws and regulations and are usually subject to severe penalties, potentially resulting in up to 50% or more of energy and revenue loss in extreme cases. Additionally, nighttime wind speeds are typically higher, but nighttime noise restrictions are also usually stricter, increasing the importance of reducing noise emissions to offset production and economic penalties.

[0108] As shown in Table 1, significant improvements can be achieved with low-frequency sound waves (such as 10 Hz–630 Hz, which is particularly useful because low-frequency sounds can travel longer distances).

[0109] In one embodiment, a wing comprising multiple alternating protrusions and valleys along its trailing edge can provide alternative aerodynamic and acoustic characteristics. The control system of a turbine with these wings can then be modified and optimized to take advantage of the new aerodynamic and acoustic characteristics. Advantages of such a system can include improved power production and aerodynamic efficiency, as well as improved operating parameters. Given that the prior controller settings have been optimized to operate the turbine to obtain minimal acoustic generation from the wings, another advantage is enhanced noise reduction capabilities.

[0110] Therefore, parameters within the turbine controller (sometimes called a Supervisory Control and Data Acquisition (SCADA) system), such as TSR and blade pitch angle tables corresponding to wind speed or rotor thrust, can be adjusted in a beneficial manner. In some cases, specialized control modes can be developed that utilize the aerodynamic and acoustic properties of an airfoil with multiple alternating ridges and valleys.

[0111] For example, TSR can be increased by 0.2 in the wind speed range of 7-9 m / s and by 0.1 in the wind speed range of 10-11 m / s, without increasing turbine noise. This improvement can be achieved by adjusting the fine blade pitch table by +0.5 degrees in the 7-11 m / s wind speed range without exceeding load limits. The net benefit is the additional electricity production resulting from the improved rotor blade lift / drag curve, combined with the reduction in noise.

[0112] For example, a sample control correction could include sensors that track sound generation / noise from the turbine. The sound generated by the turbine or the entire turbine field can then be calculated (and transmitted back) whether it is at a point on the turbine itself, within the turbine field, or at a point far from the turbine. This can be used to control and optimize turbine operation (as one of the feedback parameters controlling parameters such as speed, blade pitch angle, etc.). In one example embodiment, a maximum noise threshold can be determined, and the parameter can be controlled as a negative feedback loop to keep the generated noise below the threshold.

[0113] Specific feedback parameters can be sent in the form of control data payload data objects, which are processed by an onboard controller. The onboard controller alters the system's operating characteristics through control mechanisms such as physical actuators and motors, thereby physically changing the angle of attack or altering generator speed, turbine rotation, etc. All of these parameters can affect the total noise generated by the turbine or turbine-airfield and the overall power production.

[0114] In one aspect of this embodiment, the enhanced control parameters can be commercially used to generate additional power output or reduce noise emissions. These features can allow operators to upgrade turbines to produce higher rated power output. These features can also be used to generate specialized noise, load, or power patterns that expand the commercial applicability of the turbine when considering site-specific characteristics such as noise offsets from houses or residences. For example, if the embodiments described herein take noise reduction into account, this could allow for the placement of more turbines on a given plot during the initial phase of a wind power project.

[0115] For example, since adding serrations can reduce the overall noise of 10 turbines, it might be possible to use 12 turbines on a given plot of land. Similarly, if edge distances can be reduced due to noise reduction, the plot can be enlarged.

[0116] If additional turbines can be installed on already acquired land, this can significantly improve the levelized cost of electricity (LCOE) of a project. In other cases, wind turbine operators may expect to refurbish their wind farms with larger blades, turbines with higher capacity factors, and larger generators. The flexibility to reduce noise output or increase power output allows for a wider range of turbine platform options and improves the cost competitiveness of turbines equipped with devices according to the various embodiments presented herein. Depending on the specific circumstances, these features can be applied to onshore or offshore wind turbines.

[0117] Figure 1 This is a side front view of a horizontal axis wind turbine 10. The wind turbine 10 includes a tower 20 supported by and extending from a surface S (such as a ground surface). In turn, a horizontally extending nacelle 30 is supported by the tower 20. A hub having a rotator 40 is rotatably mounted at the front end of the nacelle 30 and is rotatable relative to the nacelle 30 about a rotation axis R. The rotator 40 receives and supports a plurality of horizontal axis rotor blades 100, each extending outward from the rotator 40. The rotor blades 100 capture incident wind W flowing toward the wind turbine 10. i This causes the blade 100 to rotate. Since the blade 100 is supported by the rotator 40, the rotator 30 will also rotate about the axis of rotation R as the rotor blade 100 rotates. The rotational motion of the rotator S can be converted into available electrical or mechanical force. In this sense, each rotor blade 100 is a structure adapted to pass through a fluid environment, where the fluid in this embodiment is ambient air. The nacelle 30 can be rotatably mounted to the tower 20 such that the nacelle 30 can rotate relative to the tower 20 about a substantially vertical axis (not shown), thereby enabling the rotor blade 100 to adaptively face the incident wind W. i Approaching the direction of the wind turbine 10. A nose cone 50, typically of a uniform parabolic shape, is shown mounted to the front end of the rotator 300 to allow the incident wind W... i Offset from the rotator by 300 degrees.

[0118] Figure 2This is a side perspective view of one of the horizontal axis rotor blades 100. The blade 100 includes an elongated body having a length L extending from a root 130 to a tip 140. The elongated body has a leading edge 110 and a trailing edge 120, wherein the leading edge 110 passes through the air before the trailing edge 120 as the rotor blade 100 moves. Here, the leading edge 110 and the trailing edge 120 are separated from each other along a chord length 125. The chord length 125 is largest near the root 130 of the blade 100 and gradually decreases in size until it reaches the tip 140 of the blade 100. The pressure side 150 of the elongated body is shown here, and the suction side 160, shown in dashed lines, is opposite the pressure side 150 of the elongated body of the rotor blade 100. In the present method, there is no alternating protrusion and valley structure 200 ( Figures 3A-3B As shown, airflow moving along the suction side 160 and pressure side 150 of the elongated body of rotor blade 100 abruptly meets at the trailing edge 120, generating turbulence and noise. The airflow moving along the suction side 160 and the airflow moving along the pressure side 150 can have different flow parameters (e.g., flow velocity) and can converge and mix at the trailing edge 120, thus generating noise. Using a structure as described in European patent application EP2016 / 058428, the abrupt mixing of air at the trailing edge is reduced, but without any additional benefit from the destructive interference of the geometry and methods described herein to further reduce noise.

[0119] Figure 3A This is a front view of blade 100 and structure 200 modified onto blade 100, the structure containing a plurality of protrusions 229 (in Figure 3B (as shown in the figure). As depicted, structure 200 can be geographically divided into multiple segments 200A-200E, each of which extends along a portion of the trailing edge 120 of blade 100. Figure 3B This is an enlarged view of the structure 200 modified onto the blade 200. As depicted, each of the protrusions 229 in the given segments 200A-200E can be geometrically identical. Furthermore, the geometry of the protrusions 229 contained in the given segments 200A-200E can differ from the geometry of the protrusions 229 contained in other segments 200A-200E. For example, as depicted, the geometry of protrusion 229A in segment 200B differs from the geometry of protrusion 229H in segment 200A. It should be understood that the arrangement of segments 200A-200E is merely exemplary, and the structure 200 can be arranged to have different numbers of segments containing different numbers of protrusions. Although Figures 3A-3B A structure 200 modified onto or attached to the blade 100 is shown. It should be understood that the structure 200 can be integrally formed with the blade 100.

[0120] Figure 3C This is a front view of blade 100 and structure 200 modified onto blade 100, the structure containing a plurality of protrusions 229 (in Figure 3D (As shown in the figure). As depicted, structure 200 can be spatially divided into structure 201A, which increases in height continuously from a tip segment 140, said tip segment extending along a portion of the trailing edge 120 of blade 100. Figure 3D As shown, the structure 201A can be divided into many segments, such as 202A-202B, such that the height of each protrusion in the protrusions 229 varies gradually relative to its adjacent protrusions. Such a configuration can be advantageous when targeting multiple frequencies of interest, or when maximum noise reduction is desired over manufacturing complexity. This type of construction is more complex to manufacture because each segment in 202A-202B must be customized for application to a specific airfoil section along blade 100. This situation may arise if a turbine manufacturer wants to create a specific 'low-noise' turbine blade for a particular market.

[0121] In this scenario, it might be desirable to create a series of alternating segments 202A-202B of multiple protrusions 229, as the rotor blade 100 will be tailored for this type of low-noise market application, necessitating mass production. In such an example, the series of alternating segments 202A-202B could be designed to knock out frequencies in the 200Hz range closer to the rotation axis R and in the 800Hz range closer to the blade tip 140. In this case, in the optimized setup, d' would be set to 23% of the local chord length to knock out 200Hz, and in the optimized setup, it would be set to 17% of the local chord length to knock out 800Hz. Such markets could essentially be refurbishment projects where power developers wish to reuse turbine foundation or tower segments but replace the blades and / or generator, or they could be region- or country-specific, such as France or the Asia-Pacific region.

[0122] This article describes many different zoning methods because the number of segments can depend on operational and configuration factors. One aspect to consider is that wind speeds encountered at different locations may vary, and different zoning methods are used to better match wind speeds to configurations. However, due to practical constraints, zoning methods may ultimately be broken down into a set of discrete zones, each with a serration of the configuration of that zone. This approach is useful when manufacturing economics are important, for example, in batch-produced zoning modifications. In an alternative variant, each individual and each serration (rather than a segment) is matched to the wind speed encountered by that particular serration. For example, this approach can be used in practical situations where accuracy is critical, despite additional manufacturing costs. This can also be useful when utilizing highly controlled manufacturing techniques such as additive printing methods (3D printing) and can be used to prepare custom or tailored serration configurations for specific practical use implementations. Different methods can be used for different levels of desired noise correction (e.g., turbines in rural areas versus turbines near residential areas).

[0123] Figure 4 This is a side perspective view of section 200B of structure 200. Section 200B may include a base section 220, which is beveled at its end portion 210 such that the edge 211 of the base section 220 is flush with the surface X of the trailing edge 120 of the blade 100 (in... Figure 9 (Shown in more detail in A-9B). This arrangement ensures minimal interference with the natural flow of air from surface X above base section 220. As shown, section 200B can have a proximal end N and a distal end D. Structure 200 can be modified or integrated into blade 100 such that the distal end D is closer to the tip 140 of blade 100 than the proximal end N. A bevel is another method that can be used to further improve noise reduction performance. A bevel design is another embodiment under consideration.

[0124] By using serrations, instead of mixing all the air flowing under the wing with all the air flowing above the wing at the same chordal position, the serrations disperse the mixing over a larger area and prevent the turbulent properties of the mixing from occurring simultaneously at one location. Some air will mix at the valleys. If the distance between these valleys is equal to half the wavelength of the sound, the noise at that wavelength will experience destructive interference and will be quieter.

[0125] like Figures 3A-3B As shown, multiple sections 200A-200E of structure 200 can be aligned along the trailing edge of blade 100. Figure 3B yes Figure 3AAn enlarged cross-sectional view of the area. This is achieved by connecting side interface 225 located at the distal end D of a given segment 200A-200E to side interface 224 (not shown, see [link]) located at the proximal end N of an adjacent segment 200A-200E. Figure 4 Each segment 200A-200E can be connected to an adjacent segment 200A-200E. In some embodiments, the side interface 225 of a given segment 200A-200E (see...) Figure 4 It can be geometrically configured to mate with or nest with the side interfaces 224 of adjacent segments 200A-200E. In some embodiments, the side interface 225 of a given segment 200A-200E may have the same but opposite geometry as the side interface 224 of the adjacent segment 200A-200E.

[0126] As depicted, segment 200B of structure 200 contains a plurality of protrusions 229A-229E, which extend parallel to the chord length 125 when structure 200 is modified onto blade 100. For simplicity, the construction of protrusions 229A-229F will be explained in conjunction with protrusion 229B. However, it should be understood that each of protrusions 229A-229F may have the same construction. As depicted, protrusion 229B may have two or more peaks 232, 234. Primary valleys 231 may be defined between protrusions 229A, 229B, and secondary valleys 233 may be defined between two or more peaks 232, 234. A specific number of valleys is not required for serration operation. However, the width of the serrations is proportional to their length, which is proportional to the chord length. Generally, the shorter the chord length, the more valleys there are.

[0127] Without structure 200, air moving along the suction side 160 and air moving along the pressure side 150 might abruptly converge and mix at a chordal position along the trailing edge 120 of blade 100, generating undesirable turbulence and noise. However, when structure 200 is modified onto blade 100, it can cause at least some of the air moving along the suction side 160 and at least some of the air moving along the pressure side 150 to mix at the primary valley 231 and secondary valley 233 of protrusion 229B. In other words, structure 200 causes some air from the suction side 160 and some air from the pressure side 150 to mix at the primary valley 231 and secondary valley 233, rather than at the trailing edge 120 of blade 100. This air mixing can generate noise.

[0128] As described above, primary valley 231 and secondary valley 233 define two zones in which air moving along the suction side 160 and air moving along the pressure side 150 can mix. The air moving along the suction side 160 can have a different flow velocity than the air moving along the pressure side 150. When the airflows interact at primary valley 231 or secondary valley 233, flow mixing and sound surges may occur. To reduce the amount of sound generated by primary valley 231 and secondary valley 233, structure 200 can be geometrically constrained to maintain a specific positioning of primary valley 231 relative to secondary valley 233. Specifically, the lowest point of primary valley 231 can be spaced apart from the lowest point of secondary valley 233 by a distance d' to reduce sound surges. The starting points of these two flow interactions (i.e., at primary valley 231 and secondary valley 233) are crucial for the initiation of sound waves and occur at the minimum values ​​of valleys 231 and 232. When a sound wave forms at the primary valley 231, its relation to another sound wave forming at a spatially defined distance d' at the secondary valley 233 is important because the interaction between the two sound waves produces a reduced sound power level. Specifically, the maximum energy within the sound wave from the primary valley 231 will interact with the minimum energy from the secondary valley 233 to cancel out the two sound waves.

[0129] In some embodiments, the height of each of the protrusions 229A-229F in a given segment 200B relative to the edge 211 of the base 211 may be the same as the height of the other protrusions 229A-229F in the given segment 200B. In other embodiments, the height of one or more of the protrusions 229A-229F in a given segment 200B relative to the edge 211 of the base 210 may be different from the height of the other protrusions 229A-229F in the given segment 200B.

[0130] Figure 5 This is a front perspective view of segment 200B of structure 200. As depicted, the height of the first peak 232 relative to the edge 211 of the base segment 220 may differ from the height of the second peak 234 in the protrusion 229B. For a given serration, there may be a first peak 232 and a second peak 234, and these peaks may have smaller valleys 233 between the two peaks and larger valleys 231 between individual serrations.

[0131] Different sawtooth lengths are possible. For example, it is thought that using "standard" sawtooths, longer lengths can reduce noise at low angles of attack. The longer the sawtooth, the higher the cost and the chance of damage. In a particular embodiment, 232 and 234 have different lengths. For example, 232 is 30 cm long, while 234 is 31 cm long. This changes the local location of swirl formation and helps to reduce its impact on the wind farm.

[0132] Furthermore, the height of the second peak 230 of protrusion 229A relative to the edge 211 of the base segment 220 may differ from the height of the first peak 232 of protrusion 229B relative to the edge 211. As depicted, the second peak 230 of protrusion 229A may be shorter by a distance d' than the first peak 232 of protrusion 229B. As shown, the lowest point of the primary valley 231 and the lowest point of the secondary valley 233 are separated by a distance d'. Since the distance d' is determined based on the lowest points of the primary valley 231 and the secondary valley 233, the distance d' can be determined without considering the highest points of two or more adjacent peaks 232, 234. As previously mentioned, maintaining the distance d' between the lowest point of the primary valley 231 and the lowest point of the secondary valley 233 is crucial for reducing the amount of sound generated by the primary valley 231 and the second valley 233.

[0133] The distance d' can be determined as a relationship between at least the sound velocity, boundary layer displacement thickness, and total local wind speed. d' can be an approximation and noise cancellation is performed at the dominant frequency. While some non-ideal factors may exist, the value of d' may have some inaccuracies; however, the noise correction benefit may be reduced at the target frequency. Given these non-ideal factors, while the relationship can be used to establish geometric configurations, there is a certain tolerance for deviations. For example, although adjacent frequency values ​​may be affected, there are still limited benefits even if manufacturing tolerances cause significant deviations. For example, values ​​such as d' can vary continuously within + / -1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, and any range therebetween. In some embodiments, the distance d' between primary and secondary valleys can be determined based on the following formula:

[0134]

[0135] The following is an example calculation:

[0136] d'=[(343m / s)(0.015m) / (0.14)(57m / s)]

[0137] d'=0.645m

[0138] Equation 1 can provide the distance d' between a primary valley and an adjacent secondary valley (such as primary valley 231 and secondary valley 233) at a specific radial position relative to the axis R (i.e., at a specific position along the length L of the blade 100). In Equation 1, U s This represents the speed of sound determined based on the operating temperature. This represents the boundary layer displacement thickness of blade 100; and U L Represents the total wind speed. Speed ​​of sound U sThe operating temperature can be determined based on the average operating temperature in the specific area where the wind turbine 10 is located, as shown in Table 2 below.

[0139] Table 2

[0140]

[0141] Boundary layer displacement thickness δ BL The boundary layer displacement thickness can be determined based on the radial positions of the primary and secondary valleys (i.e., specific positions along length L). In some embodiments, the boundary layer displacement thickness... It can be determined based on the shape of the blade 100, the chord length 125 related to the radial positions of the primary and secondary valleys, the average local flow velocity based on the radial positions on the blade, control settings, atmospheric wind, and angle of attack. The relationship is a complex one, involving many complex differential equations.

[0142] Increasing the curvature of the wing requires more complex methods to analyze the boundary layer. Boundary layer δ BL Altitude is when the local air velocity equals the upstream air velocity U. ∞ It was estimated at 99%.

[0143] Along the pressure gradient of the wing Given, where P is the pressure and x is the chord length.

[0144] For incompressible flow, the pressure gradient is:

[0145]

[0146] The flow is one-dimensional and can be controlled by conservation of mass and momentum. The shear stress on the surface is given by τ. When integrating over the control volume, the equation becomes:

[0147]

[0148] Using the Blassius approach, accurate solutions can be predicted when the flow is laminar and the pressure gradient is zero. At the stagnation point:

[0149]

[0150] The shape of the wing is approximated by a best-fit polynomial. The equation can take the following form:

[0151]

[0152] Where A, B, and C are constants, and θ is the momentum thickness.

[0153] In the turbulent region, complex shapes are approximated by the following formula:

[0154]

[0155] Some values ​​should be preset based on the available relevant experimental data.

[0156] Since solving these equations manually is labor-intensive, software based on numerical methods was used. Therefore, these parameters can be input into a program like XFOIL. TM Determining the boundary layer δ in wing analysis software BL The wing analysis software runs a simulation based on these parameters and outputs the boundary layer displacement thickness δ. BL Total wind speed U L The speed can be determined using the upstream wind speed and the speed of the rotating blade 100. The speed of the rotating blade 100 can be calculated at a specific radial location (i.e., a specific location along length L) where the primary valley 231 and secondary valley 233 are located. In some embodiments, the total wind speed U can be determined using the following equation. L :

[0157]

[0158] In equation 2, U ∞ This refers to the upstream wind speed, where r is the radial position relative to the root, and ω represents the number of revolutions per minute (rpm) of the blade (100). The upstream wind speed can be determined using an anemometer associated with the turbine.

[0159] In some embodiments, the distance d' between a given primary valley and an adjacent secondary valley can vary in different regions of the wing.

[0160] Specifically, the distance d' between a given primary valley and an adjacent secondary valley can vary depending on the radial position of the primary and secondary valleys relative to the root 130 (i.e., along the length L of the leaf 100).

[0161] As previously described, the distance d' can be based on a given operating temperature, boundary displacement thickness δ BL Total local wind speed U L speed of sound U s (See Equations 1 and 2.)

[0162] These parameters may vary depending on the radial position of the primary and secondary valleys relative to the axis R (in Figure 1 (As shown in the image). Total local wind speed U L It can be increased in the radial direction relative to the axis R (as shown in Equation 2). In other words, the closer the primary and secondary valleys are to the tip 140 of the blade 100, the higher the total local wind speed U at those points. L The larger the chord length, the greater the radial direction relative to the axis R.

[0163] In other words, the closer the primary and secondary valleys are to the tip 140 of the leaf 100, the smaller the chord length 125 at those points. Based on equations 1 and 2 and the relationships explained above, it can be concluded that the distance d' can decrease towards the tip 140 of the leaf 100 and increase towards the root 130 of the leaf.

[0164] In the optimal setting, the string relationship d' between the primary and secondary valleys may be half the wavelength of the dominant local frequency.

[0165] This setup provides optimal conditions for the destructive interference of the first and second sound waves. The dominant local frequencies at the primary and secondary valleys may be specific to the radial positions of the primary and secondary valleys.

[0166] The dominant local frequency may depend on the boundary displacement thickness δ BL The boundary layer displacement thickness may vary depending on the radial position of the primary and secondary valleys. As the radial position changes, the chord length 125 also changes, and therefore the boundary layer displacement thickness δ... BL It will change. Boundary displacement thickness δ BL The larger the value, the lower the dominant frequency. Conversely, the smaller the value, the lower the dominant frequency.

[0167] refer to Figures 3A-3B The distance d' between primary and secondary valleys contained in a given segment 200A-200F can be the same. In some embodiments, the distance d' between primary and secondary valleys contained in a given segment 200A-200F can be different from the distance d' between primary and secondary valleys contained in each segment of other segments 200A-200F. The distance d' between primary and secondary valleys contained in a given segment 200A-200F may depend on the radial position of the segment relative to the axis R. The radial position of a given segment 200A-200F can be based on the average local flow velocity seen in any given segment 200A-200F, where the length of the segment is the controlling factor. For example, to simplify the equations, the average radial position can be derived, which represents the midpoint of the values ​​seen in a given segment.

[0168] In some embodiments, each segment 200A-200F may have a boundary displacement layer thickness value δ. BL δ represents the average boundary displacement layer thickness determined using the median of the radial positions of the given segments 200A-200F. BL Table 3 shows a non-limiting example.

[0169] Table 3:

[0170] Partial Number Distance from the tip (m) Boundary layer displacement thickness (mm) 200A 1 0.5 3.8 200B 2 3.5 5.0 200C 3 6.5 5.8 200D 4 9.5 6.6 200E 5 12.5 7.4 200F 6 15.1 8.2

[0171] Similarly, each segment 200A-200F can have an approximate total wind speed U determined using the radial position at the average midpoint of a given segment 200A-200F. L The distance d' between the primary and secondary valleys in a given segment 200A-200F can be determined based on the approximate boundary displacement layer thickness δ of the given segment. BL and approximate total wind speed U L To determine.

[0172] The number of segments can vary, for example, a set of continuous segments or a discrete number of segments (e.g., 2, 3, 4, 5, 6, 7, 8, 9, 10). When determining the number of segments, a trade-off between complexity, efficiency, and cost needs to be considered. For example, on a 2MW turbine with 45m blades, there could be a total of 15 meters of sawtooth. These 15 meters could be divided into 6 discrete segments, each with a length approximately equal to the median of the grouping. Each segment faces a different wind speed (e.g., due to radial positioning at a far or near end from the root), and therefore, each segment can use a different sawtooth configuration, since different wind speeds correspond to different frequencies to be attenuated. The wind speed can vary as a function of the radial distance from the root, and this relationship can be linear. Different values ​​of d' can be used between each segment. In another embodiment, d" can also vary depending on the segment.

[0173] like Figure 3B As shown, the distance d' between the primary and secondary valleys may be largest in segment 200F (farthest from the tip) and smallest in segment 200A (closest to the tip). The magnitude of the distance d' can gradually decrease from segment 200F to segment 200A along segments 200B-200D. As described, d' can be determined in sections, or it can be determined continuously or per tooth, depending on actual installation and operational constraints. Therefore, the value of d' can vary as a function of the distance from the tip or as a function of the distance from the root (e.g., how far or near the tooth). For example, d' for a particular tooth can be based on the wind speed encountered at the midpoint of the tooth. Other points (e.g., the near or far edge of the tooth) can be chosen.

[0174] In another embodiment, the distance d' between a given primary valley and an adjacent secondary valley can be based on a specific radial position of the given primary valley and adjacent secondary valley relative to axis R. This function can be linear. In this embodiment, structure 200 may not be divided into segments 200A-200F, and the distance d' between a given primary valley and an adjacent secondary valley can be based on a specific boundary displacement layer thickness δ corresponding to the radial position of the primary valley and adjacent secondary valley. BL and a specific total wind speed U LThe distance d' can be calculated using equation (1). This, in turn, will cause the distance d' of structure 200 to gradually decrease toward tip 140. In all cases, using equation (1) or the median of the radial positions of given segments 200A-200F, and taking the chord length 125 as an example, the value d' should be between 5% and 45% of the local chord length 125. More specifically, d' should be intended to be between 10% and 25%, and more preferably 18%-20%. This ensures that no inappropriate aerodynamic loads are placed on the wing, and that the load on the structure itself is controllable throughout the relevant operating conditions. This range achieves optimal performance in noise reduction because the local frequencies of concern tend to be generated with wavelengths corresponding to these d' values. In addition, given the constraints of increasing the load when increasing the percentage of chord length 125 and the performance degradation when decreasing the percentage of chord length 125, this range has been found to be optimal for most cases. Peel forces must be considered, especially if the structure exceeds 25%, the choice of adhesive solutions and materials will become limited and expensive. In specific cases where wind turbine blades are longer than 75 meters, the flow velocity at the tip may generate a load, so the expected value of d' should be 10%, 11%, 12%, 13%, 14%, or 15%.

[0175] like Figure 5 As shown, d” is the height difference between the two peaks (232 and 234 in this example). Variations in d” result in one peak being higher than the other, creating different axial positions for air mixing. For example, d” can be measured as the height of the left peak 232 minus the height of the right peak 234, where a positive value indicates that the left peak 232 is higher, and a negative value indicates that the right peak 234 is higher.

[0176] For example, the choice of which peak is higher can be determined based on the direction of the fluid. For instance, if the right side is the portion of the blade furthest from the hub, the right peak is higher in some embodiments, and the left peak is higher in others.

[0177] As mentioned, different axial positions affect the swirling flow because there are alternating axial positions in the flow. A layman's description of alternating axial positions of the flow includes the first peak extending a few millimeters further than the second peak, to give d".

[0178] These affect noise spikes and tonal aspects by shifting sound from one frequency to another. Specifically, shifting lower-frequency noise to higher-frequency noise may be desirable because the noise travels a shorter distance from the turbine, or attenuates faster in the atmosphere than lower-frequency noise (e.g., with shorter wavelengths). Different versions of the d” configuration were considered.

[0179] In the first embodiment, each d” has the same orientation, meaning that either the left or right peak is always higher than the other peak. As mentioned above, this can be based on which side is closer to the hub and which side is farther away from the hub.

[0180] In the second embodiment, each d” can have an opposite orientation, meaning the sawtooth alternates between higher left and right peaks. For example, in the first embodiment, d” is always a positive or negative value. In the second embodiment, d” alternates between positive and negative values ​​(e.g., higher on the left, then higher on the right, and so on).

[0181] The d” value or configuration can be constant across the serrations, or in some embodiments, it can continuously vary based on results identified at specific points along the blade, for example, the distance from the hub. In another variation, separate segments exist, each with a different d” value or configuration. This variation is easier to manufacture but less targeted compared to the continuously varying version for each serration, though both can be used to improve the noise characteristics of turbine blades.

[0182] Finally, each segment can also have a different configuration, and this can depend on the type of fluid flow experienced at each segment. The value / configuration of d” can be determined based on a combination of contributing factors from d’, w’, and w”, as each of these contributing factors may contribute to the overall noise tuning characteristics of the sawtooth. For example, d’, d”, w’, and w” can all be selected together to match the overall noise correction of the turbine or the turbine airport as a whole with the desired result, recognizing that the selection of d’, d”, w’, and w” may also have other effects on lift, drag, weight, or other operation-related aerodynamic factors. For example, d” can be selected or configured to attempt to convert undesirable sounds into frequencies that might deter animals.

[0183] refer to Figure 5 In some embodiments, the radial distance w' between the primary valley and the adjacent secondary valley can be selected and determined based on the distance d' between the primary valley and the secondary valley.

[0184] The radial distance w' between the primary valley and the adjacent secondary valley can be determined based on the distance d' and the dominant frequency to be reduced. In addition to d', altering w' and w" (where w" is the radial distance between the first peak 232 and the second adjacent peak 234) may have the additional benefit of allowing each blade length to have more or fewer ridges and valleys, thus allowing for further noise reduction in a given segment of a blade known to produce more noise (in the case of reduced w' and w"). For example, if a reduction in higher frequency bands is desired, additional ridges per radial length may be needed because the wavelength length is reduced, and therefore increasing w' and w" may have a beneficial effect.

[0185] In some embodiments, the radial distance w' can be determined using the following equation:

[0186]

[0187] Example equations are given below:

[0188] w'=[((0.645m)(0.07) / (580Hz / 3))×1000]

[0189] w'=0.233m

[0190] In Equation 3, the distance d' is multiplied by a constant K. In some embodiments, the optimal value of the constant K is 7% or 0.07. However, it should be understood that the value of the constant K can be any value from 1% to 99% or from 0.01 to 0.99. Then, according to harmonic theory, the product is divided by one-third of the dominant frequency in the frequency band. F can represent the dominant frequency at a specific radial location where the primary valley and the adjacent secondary valley are located. The dominant frequency can be determined using Equation 4.

[0191] Equation 4 presents a coefficient of 0.07, but other values ​​are also possible.

[0192] The total wind speed U in Equation 3 L and boundary layer displacement thickness δ BL The value can be compared with the pre-determined total wind speed U. L and boundary layer displacement thickness δ BL same.

[0193] Example values ​​for w' and w" are as follows: Figure 3A / Figure 3B The diagram shows a partial representation. For example, the value of w' can similarly depend on discrete, stepwise progression from part to part, or in another embodiment, each sawtooth can be evaluated such that each sawtooth is configured individually.

[0194] w'(mm) w"(mm) 200A 12.0 12.0 200B 20.7 20.7 200C 27.0 27.0 200D 33.7 33.7 200E 42.6 42.6 200F 51.1 51.1

[0195] In some embodiments, F may represent the dominant frequency at a specific radial location in the segment 200A-200F, wherein the primary valley and the adjacent secondary valley are contained within the location (i.e., along the length L of the blade 100).

[0196] The shear of the end portion 210 can also vary along the length L of the blade 100. The shear of the end portion 210 can be modified such that the flow can move from the trailing edge surface X to the base 220 of the structure 200 over a larger surface area at a smaller radial location. Given the reduced flow velocity, the shear in this case may be more pronounced. In this situation, the flow velocity is lower, and therefore its vector can change without transitioning to turbulence. In contrast, in the case of other radial sections, the shear may be less pronounced to allow for reduced flow vector changes even with increased local flow velocities. Additionally, sinusoidal geometry can be incorporated into the shear to induce local flow acceleration and prevent turbulence and noise at the trailing edge.

[0197] In some embodiments, the radial distance w” between the two peaks of a given protrusion can be 1 / 10 of the length of d’.

[0198] Furthermore, the values ​​of d', d”, w', and w” are determined with aerodynamic considerations in practical applications. The aerodynamic lift performance of a wing exceeding its drag can be improved by modifying the aforementioned values. Additionally, in the case of a wing designed to work together in a system, it can be customized to improve wake recovery. This is the case, for example, with wind turbines, where the current wake propagation is strongly driven by the aerodynamics of the outer portion of the turbine blades, which is the application area of ​​sections 200A-200F, as previously described. Changing the effective chord 125 of blade 100 for d' and d” will inevitably alter the aerodynamics. The degree of variation along a specific radial segment of the blade must be considered, taking into account information about the turbine's operating parameters and climatic conditions, including desired noise reduction. Changes in w' and w” alter the number of aerodynamic elements interacting with the flow, and thus change the flow pattern. For example, under highly turbulent wind conditions, increasing the values ​​of d' and d” and decreasing the values ​​of w' and w” will result in more fluid contact with structure 200 and make the flow more ordered, thereby reducing noise caused by TE-TBL noise. To influence the flow pattern in a desired manner, specific geometries of one or more of the peaks 232 and 234 can be modified. This can include deviating one or more of the peaks 232 and 234 from the centerline 262 of the base section 220 or rotating it, or if the protrusion 229G forms an angle 'a' with this base section 220, such as... Figure 8DAs shown, this deviates from the centerline 261 of the protrusion 229G. This deviation or rotation induces momentum transfer within the fluid in the downstream position and allows the flow to regain energy more quickly by inducing free-flow velocity. With increasing values ​​of d' and d” and decreasing values ​​of w' and w”, the deviation or rotation will be less than with decreasing values ​​of d' and d” and relatively increasing values ​​of w' and w”. This is because, with increasing protrusion 229G, such a large degree of deviation or rotation is not required to achieve the desired effect. It must be noted that this operation is performed in areas where noise is not a problem (such as in offshore locations), or if noise is a problem, the geometrical variation allows operation within permissible noise limits. In all cases, the primary objective is to generate as much aerodynamic lift as possible within load limits, increase wake recovery, and minimize noise emissions or impact on wildlife. Therefore, given the physical limitations of the turbine structure ( Figure 1 The effects of this invention can be tailored to specific properties desired, whether for maximum noise reduction or power performance. Optimal noise reduction occurs when the values ​​of d' and d” correspond to the dominant frequencies generated by the wing or control surfaces. Optimal power performance occurs when the values ​​of w' and w” correspond to the average flow velocity, where the sum of the values ​​of w' and w” (in millimeters) is equal to or less than the flow velocity (in meters per second). With this in mind, blade designers may keep these considerations in mind when designing wings for specific commercial jurisdictions or wind conditions. In a recent field event, example section 200E, containing 300 mm of d', 10.2 mm of d”, 31 mm of w', and 30 mm of w”, as part of a series of serrated sections 200, provided a tangible acoustic benefit of 3 dB reduction compared to standard serrations.

[0199] Reduced wake is beneficial for installations in modified configurations, as downstream turbines will benefit from increased wake mixing and higher flow velocities. This, in turn, increases revenue generated by the wind farm, as the overall wind speed impacting the rotor will be higher. Losses due to wake effects in commercial wind farms have been identified as high as 20%. Furthermore, far-field wake effects are now being recorded on wind farm operators' balance sheets, as one offshore wind farm blocks another. This can occur as far as 100 km away.

[0200] Flow patterns can be trapped in the wake and persist over extended distances. These large-scale congestion effects can impact site selection and increase costs for developers. This is a relatively new area within the wind energy industry, and therefore, technologies that can mitigate wake effects in a modifiable manner are highly anticipated.

[0201] Reduced flow velocity fluctuations also have a beneficial effect on turbine fatigue and structural loads, meaning less maintenance is required for operating assets. Increasing the flow velocity to be closer to the free-flow velocity can achieve this, and is the desired result.

[0202] Reduced wake also benefits turbine designers and wind farm developers who want to include as many turbines as possible in a given area, whether on land or at sea. Additionally, the aerodynamic and acoustic benefits can be modeled using high, medium, and low-fidelity computational models to simulate the impact on the levelized cost of electricity (LCOE). High-fidelity models can be large vortex simulations (LES), for example, while low-fidelity models can be wind resource assessments, using WaSP for site selection and energy productivity calculations. Developers using tools like WaSP can simulate the effects of wake variations in wind farms and model how technology can help achieve this result. This, in turn, can guide wind power projects from unfinancing to financing and funding.

[0203] The techniques discussed in this article can also be combined with other technologies to beneficially improve the performance of wind turbines and wind farms, and to improve downwind rotor washing. These can include, but are not limited to, vortex generators, winglets, leading-edge corrosion protection technologies, or devices to improve the lift of the main rotor blades. Wake reduction is achieved through a mechanism of momentum transfer between the faster-moving free-flow velocity and the slower-propagating wake. When these two flows interact and mix, momentum transfer occurs, and the net flow velocity increases as the wake gains momentum from the free flow.

[0204] Figure 6 This is a two-dimensional graph showing the sound level (dB) produced by blade 100 as a function of frequency (Hz). The graph was created based on data generated through wind tunnel testing. The fan used for the wind tunnel testing produced a wind speed of 75 m / s. Trend line 302 represents the sound level (dB) of blade 100, which indeed has a structure 200 modified onto or integrated into blade 100. Trend line 304 represents the sound level (dB) of blade 100, which has a structure 200 modified onto or integrated into blade 100. As depicted, when the frequency is below approximately 3000 Hz, the sound produced in blade 100 with structure 200 is less than that produced in blade 100 without structure 200. As depicted, there is a significant decrease at point 306 when the frequency is 630 Hz. Point 306 may be the location where destructive interference reaches its maximum effect.

[0205] like Figure 6 The study observed a technical improvement between the non-serrated control test sample and the serrated test sample, namely a reduction in sound level (dB).

[0206] Figure 7AThis is a side perspective view of segment 200B according to an embodiment of the present invention. Segment 200B may include a base segment 220 and a plurality of protrusions 229A-229G.

[0207] For simplicity, the construction of protrusions 229A-229G will be explained in conjunction with protrusion 229G. However, it should be understood that each of the protrusions 229A-229F may have a similar construction. As depicted, secondary valley 252 may be confined between the first peak 242 and the second peak 244.

[0208] As depicted, the tip of the first peak 242 may be gradually obliquely truncated along the centerline 246 from the first height 242A to the second height 242B. The first height 242A may be smaller than the second height 242B. Similarly, the tip of the second peak 244 may be gradually obliquely truncated along the centerline 248 from the first height 244A to the second height 244B. The first height 244A may be smaller than the second height 244B. As shown, the second peak 244 may define a portion of the edge interface 226 of the segment 200B. The oblique profile of the protrusion 229G may allow the space to gradually decrease over time so that the two different flow velocities interact and converge in a more progressive manner to prevent any interaction that would generate increased turbulence and noise. In this way, the oblique profile of the protrusion 229G may be used to reduce the initiation of noise compared to a blunt structure with a 90-degree angle. Therefore, the oblique variation provides practical benefits, and the type of oblique profile (e.g., angle and shape profile) may affect the level of improvement.

[0209] Figure 7B A side view of the protrusion 229G is shown. As shown, the second peak 244 may be obliquely cut along the centerline 248 between the first height 244A and the second height 244B. In some embodiments, the tip of the protrusion 229G may be rounded (shown at the first height 244A). In some embodiments, the base segment 220 may include a recess 254 to align segment 200B with the trailing edge 120 of the blade 100. For mounting, the recess 254 may be used to engage the base segment 220 with the blunt trailing edge 120 of the blade 100.

[0210] Figure 7CA top perspective view of a portion of section 200B is shown. As shown, the base section 220 may be beveled at the end portion 210 such that the edge 211 of the base section 220 is flush with the surface X of the trailing edge 120 of the blade 100. The degree of beveling (which determines where the maximum thickness distance 256 begins) is related to the distance from the valley 252 and local input parameters. As described above, the local flow velocity determines the beveling geometry. Ideally, the beveling angle would be smaller when the base section 220 is applied at a different radial location to allow for a reduction in flow vector changes from the trailing edge 120 in the event of increased local flow velocity. Acute beveling angles can range from 1 degree to 10 degrees. Less severe beveling means that the length from the edge 211 to the maximum thickness distance 256 may increase, meaning that the thickness will gradually accumulate more. The edge 211 can be represented using sinusoidal, curved, or wavy flow surfaces, allowing the flow to be directed to specific useful locations above the base section 220 aligned with one or more valleys 252. This flow can adhere to the surface of the base section 220, and therefore does not generate turbulence or unwanted noise.

[0211] As the local flow velocity increases, the degree of oblique cut of these protrusions located at further radial positions should be less. First, the thickness of the protrusions is small, thus reducing the thickness that mates with the trailing edge of the blade. Second, the flow vector should not change too much, as any large change risks turning the flow into turbulence. This arrangement ensures that, at the trailing edge 120, the disturbance to the natural airflow moving above the suction side 160 and pressure side 150 of the elongated body of the blade 100 is minimized.

[0212] Figure 7D A cross-sectional perspective view of an example valley geometry 500 for the structure of alternating protrusions and valleys 200 is shown. Figure 7D Can be with Figure 7CA comparison is made, with a cut at 260. According to one embodiment, a recess 531 exists at the starting point of the base section 520 and extends toward the apex of the valley 532. The recesses 531 and 532 are located on the pressure side of structures 200 and 300, and the recess 533 is located on the suction side of the structures, wherein the recesses 531, 532, and 533 are diagonally opposite each other to guide flow into a preferred downstream forming layer, which will transmit less acoustic energy. The depth of the recesses 531, 532, and 533 can increase as it travels from the base section 520 toward the apex of the valley 532. Similarly, this is to minimize interference with the natural flow path of air moving above the suction side 160 and pressure side 150 of the elongated body of the rotor blade 100 at the trailing edge 120. The valley on the suction side is offset relative to the valley on the pressure side. This guides the flow so that it does not collide at 231 but rotates around each other. Furthermore, the recess positioned more towards the tip section 140 can have a smaller recess of about 1 mm, while the recess positioned more towards the root 130 can have a larger recess of about 5 mm. This is due to the difference in local flow velocity. The flow velocity near the tip is much higher and cannot withstand large changes in its vector without becoming turbulent, while the flow near the root can withstand a greater degree of vector change.

[0213] In both primary valley 231 and secondary valley 233, such geometric configurations / geometry can also be considered. The generation of micro-vortices and the associated aerodynamic changes of the rotor blades 100 may benefit the improvement of aerodynamic lift relative to drag and wake recovery. In this case, improving aerodynamic performance and reducing drag by generating these micro-vortices causes a significant reduction in the flow velocity behind the rotor. When this flow velocity is compared with the mean free flow velocity, the difference is even greater; this, in turn, improves momentum transfer downstream of the wake and reduces the impact of the wake on the downstream turbine by increasing the flow velocity for energy harvesting in the downstream turbine.

[0214] For example, the depressions can be slight and can be provided in two or more alternating valleys. When the depressions are diagonally opposite each other, vortices can be induced, which improve the aerodynamic quality of the wing, either alone or in combination with other wings. The wing can operate in a system or an array of wings, for example, the wings being positioned to utilize the vortex phenomenon.

[0215] For example, in the case of wind turbines, it improves the turbine's performance, but also improves the wake, and thus improves the performance of downstream turbines.

[0216] Figure 8A , 8BFigures 8C and 8D show side views of section 200B, in which protrusions 229G connect to the trailing edge 120 of blade 100 at pressure side 150, suction side 160, and both pressure side 150 and suction side 160, respectively. Figures 8A-8C As shown, multiple variations are possible regarding the locations where structures can be joined and / or attached together.

[0217] In some embodiments, such as Figure 8A As depicted, the end portion 210 of the base section 220 of section 200B is obliquely cut between the "X" marks on the surface of the trailing edge 120 of the pressure side 150 until it meets the top portion of the base section 220. The end portion 210 may be integrally formed with the base section 220 or may be attached to the top portion of the base section 220.

[0218] In another embodiment, such as Figure 8B The specified variation illustrates the same situation, except that section 200B is connected to the suction side 160 of blade 100.

[0219] like Figure 8A and 8B As shown, the base section 220 can be parallel to the surface "X" of either the pressure side 150 or the suction side 160. According to another embodiment, the end portion 210 of the base section 220 can be attached to both the pressure side 150 and the suction side 160, such that the base section 220 is parallel to the chord length 125. In an alternative embodiment, the base section 220 can also be at an angle to the chord length 125.

[0220] The end portion 210 of the base segment 220 can be bonded to the surface “X” of the blade 100 using an adhesive. The adhesive can be made of biological or non-biological based materials, such as UV-resistant ABA or ABS. The end portion 210 can be made of a flexible material that can conform to the local thickness of the trailing edge 120. The technical advantage of using an adhesive and having an end portion 210 made of a flexible material is that it allows bonding to be performed without needing to know the exact thickness of the trailing edge 120. In practice, this reduces uncertainty during the installation of the structure 200. Installation can be performed by applying adhesive to the end portion 210 of the base segment 220, aligning and securing the segment 200B to the trailing edge 120 using the recess 254, and applying contact force to adhere the segment 200B to the trailing edge 120. Although… Figure 9 A-9C shows that segment 200B of structure 200 is connected to blade 100. It should be understood that structure 200 can be integrally formed with blade 100.

[0221] In some embodiments, such as Figure 8DThe depiction shows that segment 200B of protrusion 229G and base segment 220 can be at an angle 'a' relative to each other. Variations of angle 'a' are possible, and many different non-limiting illustrative variations are presented below. Although angles can be described, they may also vary due to manufacturing tolerances and processes. Other variations are considered.

[0222] Angle “a” is defined between the centerline 262 of the base section 220 and the centerline 261 of the protrusion 229G.

[0223] In this case, the centerline 262 is parallel to the surface “X” of the pressure side 150 at the trailing edge 120, although it can also be parallel to the surface “X” of the suction side 160 interchangeably.

[0224] Angle 'a' can be between (+ / -) 0.5 degrees and (+ / -) 6 degrees. In some cases, the material selection for the base section 220 and the protrusion 229G allows the protrusion 229G to bend due to aerodynamic forces during operation, achieving the desired angle 'a'. In other cases, the material may be very rigid, making angle 'a' desirable in the design of the base section. This angle allows the generated airflow to align with the naturally occurring wake trajectory behind the protrusion 229G. This can be determined by the wing's angle of attack. Therefore, the optimal angle is the result of a site-specific consideration of the blade's operating angle of attack. Figure 2 ).

[0225] For example, wind turbines operate most of the time at wind speeds below their rated power, where the angle of attack of the blades ( Figure 2 The angle of attack is between -1 and -3 degrees. Therefore, in this case, the expected angle of attack would be -2 degrees.

[0226] Therefore, in the rotor blades ( Figure 2 An angle "a" can be introduced during the design phase of the turbine ( Figure 1 The operation details are explained, and the resulting load on section 200B is also reduced, and stripping and delamination are prevented.

[0227] This peeling force can cause section 200B to detach, thus rendering the purpose of this invention ineffective. This peeling force occurs when there is a pressure difference between the suction side and the pressure side of the protrusion 229G.

[0228] To reduce the impact of this peeling force, a suitable serrated material can be used, possessing sufficient flexibility to deflect into the resulting wake field and adjust to the varying pressure fields applied upon it. This material can be polyurethane or a thermoplastic polymer or elastomer containing this degree of elasticity. A novel benefit of such materials is that they passively achieve the desired angle of attack in response to surrounding pressure differences.

[0229] Noise Correction Variation: In an alternative variation, instead of noise cancellation or in addition to noise cancellation, the plurality of protrusions and valleys are adapted to generate or correct noise such that the noise is generated in the desired frequency band.

[0230] The emitted frequency range will be 20-200 kHz. Humans can hear up to 20 kHz, but the average adult hears it at around 15-17 kHz. The purpose of this technology is not to generate a frequency band that is audible and annoying to humans, but rather to signal to bats or other animals that a large object is blocking their path and that they should move away. Since most bats echolocate in the 20-80 kHz range, this will be the dominant frequency band for emitting noise / sound, but the technology can also be tunable, allowing it to be targeted at specific species.

[0231] For example, brown bats use calls in the 25-30 kHz range, so if a known population requires protection, a zigzag pattern can be applied to generate that frequency band. Additionally, since different bat species are known to fly at different wind speeds, the specified atmospheric wind speed determined by the turbine's SCADA data and the relevant effective local wind speed on the turbine blades (determined by the controller via RPM) can be used to inform the exact geometry of the feature.

[0232] In this variation, multiple protrusions and valleys are configured such that the generated noise is in a desired frequency band, which is based at least on a frequency band that repels various types of animals (such as birds, bats, fish, insects) at a given specified local wind speed (e.g., a high-frequency band outside the range of human hearing).

[0233] The geometry of this feature will be located in the outermost radial segment, close to the tip of the modified serrated blade. There are two reasons for this—first, it is expected that your noise source will be able to capture the entire sweep area of ​​the rotor that animals (e.g., bats) should avoid, in order to create a 'clearance zone', and second, this is the area where the highest speed flow of the highest frequency sound waves can be generated.

[0234] A sawtooth geometry will contain geometric features that generate noise when air passes through or through them. The precise geometry of the features determines the frequency of the emitted noise, with smaller geometric features producing higher frequency emissions. Geometry used to generate a specific frequency can be pores, holes, slits, rounded corners, recesses, bevels, etc.

[0235] By analogy, this method can be conceptualized as blowing air onto the top of a glass bottle.

[0236] Figure 9 An example sawtooth is shown, in which a deterrent mechanism adapted to generate sound at a specific frequency is built into the sawtooth. Figure 9Figure 902 illustrates an example aperture / hole whose diameter is selected to generate sound within a deterrent frequency range. Apertures of different sizes can generate sound within different frequency ranges, and in some embodiments, combinations of different apertures are used together. The aperture works in conjunction with the sawtooth to improve the sound profile by generating sound at the frequencies of interest and interfering with unwanted noise; thus, in one embodiment, the sawtooth has both a sawtooth geometry and a noise-generating aperture. The aperture may be located on the distal sawtooth, but in some embodiments, the aperture may be located on multiple sawtooths near the distal edge (e.g., not limited to the previous sawtooth). Additional apertures allow for the generation of sound of varying amplitudes and can be adapted, for example, to a specific species as a deterrent target.

[0237] Deterrence is desirable because the impact on wildlife affected by an incident can be replicated. For example, birds and bats or insects in an ecosystem might be desirable, and if they are deterred by noise, harm could be reduced or prevented, thereby improving the adoption of green technologies.

[0238] Example methods for manufacturing and application of the structure: Section 200B can be manufactured using injection molding, resin casting, laser or waterjet cutting, or 3D printing. Alternative methods, such as stamping and material forming, are also considered.

[0239] In one embodiment, structure 200 can be manufactured by injection molding, thereby replicating the design in a tool capable of manufacturing multiple components. The materials used in the injection molding can be suitable for wind turbines and may include UV-resistant plastics.

[0240] An example of such a material could be thermoplastic polyurethane (TPU), which also has the beneficial property of being recyclable. TPU is flexible, and its advantage lies in the fact that it is less likely to break during installation and, during operation, bends with the airflow as the wind turbine blades change their RPM, speed, and angle of attack. This allows for improved performance and reduced loads on the wind turbine. In practical variations where structure 200 is flexible (e.g., not necessarily TPU), structure 200 can be “bent” to a specific angle as described herein due to stresses and forces acting upon it during operation. This can be useful in methods where the material is specifically selected or provided with a geometry such that this occurs at a specific wind speed or combination of forces acting on structure 200.

[0241] Bending can be permanent or temporary (e.g., only when a force is applied). In another variation, the geometry of the structure can be adaptive and modifiable, allowing the amount of flexibility or bending to be controlled during or after the manufacturing process. Examples of adaptations for controlling the amount of flexibility can include controlling the material composition or material structure of the materials used, such as altering the base ratios, structure, or molecular weight of the base compound, or other manufacturing process parameters, by controlling the manufacturing process. Manufacturing processes can include altering how the internal lattice structure operates to modify intermolecular forces, using different combinations of plasticizers, using different combinations of materials, changing polymer processing methods (melting, injection molding, molding, cooling time, temperature), etc. These process parameters can be combined with desired operating characteristics (such as RPM, speed, and angle of attack) to configure flexibility to match the desired angle. These can be combined with turbine control and sensor feedback to help improve the overall efficiency of the system.

[0242] Materials such as TPU also possess beneficial properties, namely their ability to accommodate minute imperfections in molding. In this way, surface finish or texture can be modified to achieve these beneficial properties. An example of such a property is the creation of hydrophobic surfaces that allow for self-cleaning. In biomimetic, this is known as the 'lotus effect,' because the hydrophobic properties of a lotus leaf allow rainwater to flow off its surface, carrying away dirt and dust. Hydrophobic characteristics are beneficial for structures like those of this invention, applied to wings, due to the long-term impact of atmospheric pollutants on wind turbines' performance. Surface textures can be formed through material deposition or by laser removal, which can achieve the granularity required to reveal such surface properties. Besides applying surface textures to molds, they can also be applied directly to TPU via laser or by applying pressure, while the TPU remains malleable.

[0243] In another variation, flexibility properties can be modified on a demand-based basis, allowing certain characteristics to be altered after installation rather than being set at manufacturing. This increases deployment flexibility. These modifications can include configuring the thermoplastic by reprocessing it after manufacturing to change its properties, or attaching or modifying its physical shape to alter its bending behavior.

[0244] This structure 200 may include alignment tabs that allow for easy installation and alignment with the trailing edge of the wind turbine blade. Double-sided tape is used in front of the tabs to apply adhesive to the base section and adhere the structure to the surface of the trailing edge of the blade.

[0245] Double-sided tape acts as a dam in this way to prevent adhesive spillage. Additionally, tape cut into a zigzag pattern can be applied to the leading edge of the base section, working in conjunction with multiple adjacent protrusions to guide the flow towards the valley, thus enhancing its operational efficiency.

[0246] Structure 200 consists of multiple sections 200A, 200B, 200C, 200D, 200E, and 200F, each with a length between 490mm and 510mm, ensuring that they do not cause any obstruction at the height of the wind turbine blade.

[0247] Multiple variants of sections 200A to 200F can be selected, which can represent variations of d', d”, w', and w” of a given local average blade section used on a wind turbine blade (e.g., the optimal combination of d', d”, w', and w”). Different optimal combinations may be possible for a given use case.

[0248] In this way, as the turbine blade size varies with different turbine configurations, different allocations of sections 200A to 200F can be selected to suit or approximate specific turbine types and site requirements. Due to practical non-ideals, a degree of inaccuracy may exist.

[0249] Noise reduction, power improvement, or the generation of certain noise characteristics to deter bats may be beneficial for the specific site in which they are used. As a non-limiting example, during experiments, candidate methods that yielded good results included having each leaf composed of selected segments 200A to 200F, which together correspond to 33% of the leaf length. Other variations are possible.

[0250] In other embodiments, structure 200 can be manufactured using 3D printing. The materials used in 3D printing can be suitable for wind turbines and may include UV-resistant plastics. To manufacture structure 200 using 3D printing, design files can first be uploaded to a computer, which then sends printing commands to a 3D printer, which then manufactures structure 200 according to its material adhesion method.

[0251] Finally, another manufacturing method could be laser or waterjet cutting, whereby the design file is uploaded to a computer, and the computer then sends a cutting command to the laser or waterjet cutting head, which then conforms to the design file.

[0252] In any of the above cases, the design documents can be refined by computational fluid dynamics (CFD) simulations, which can be used to estimate the relative sound generation or aerodynamic characteristics of the structure 200 described above, as well as the configuration of the rotor blades of the horizontal axis wind turbine.

[0253] In other embodiments, structure 200 can be adhered to the wing using adhesive or double-sided tape. In other instances, single-sided tape can be used for any edge of the base section 220, which additionally provides beneficial aerodynamic characteristics. The tape can interact with boundary layer flow conditions and produce beneficial flow characteristics. This can include covering any sharp edges that would cause the flow to become turbulent, or the tape can be cut to take advantage of its thickness and low profile, thereby forcing the flow to move in the same beneficial manner as in this invention. That is, the tape can be cut in a zigzag or V-shape, the V-shape causing the flow to form small vortices at the bottom of the V. The application can occur in the context of blade manufacturing in a factory, or in the context of modification to a wing (on the ground or in the air).

[0254] In other embodiments, in addition to structure 200, alignment of structure 200 with the trailing edge of the wing can also be achieved by using and placing an object. This object can be a minimum width of thick foam tape, as the foam tape can be attached to structure 200 and allows installation technicians to place structure 200 close to the curved trailing edge or wing receiving structure 200, and acts as a guide for placement in the chord orientation of the wing. This object can be placed on structure 200 after manufacturing and can be similar to... Figure 7B The recess 254 is integrally recessed within the structure 200. This recess 254 or notch, which is removed from the structure 200, can also serve as a guide for the placement of the structure 200.

[0255] It should be understood that the structure 200 and configuration of the rotor blades of a horizontal axis wind turbine described above can also be applied to vertical axis wind turbines and both of any size.

[0256] Figure 10 This is an example wing / flow control shape for reference. As shown in Figure 1000, the shape of the wing leads to technical challenges in evaluating the boundary layer, and in some embodiments, numerical methods are used to approximate or estimate various properties of the boundary layer.

[0257] The improvements described in the above embodiments can be equally well applied to a variety of other types of wings (with necessary modifications, where such modifications are relevant), regardless of their aerodynamic design, including but not limited to high-altitude wind power (HAWP) units, tidal turbines, kite-type wind turbines, energy kites, urban wind turbines, aircraft wings, marine wings, gliders, drones, and others. The methods described herein can be applied to wind turbines with fewer or more blades than those described in the examples to improve the operating efficiency and noise reduction capabilities of wind turbines, reduce vibration, load, maintenance costs, and mechanical wear, and improve the scalability and marketability of such wind turbines.

[0258] The wing configuration described above can be used for aircraft such as commercial airliners, military jet aircraft, helicopter blades, helicopter wings, civil aircraft, drones, and other similar aircraft.

[0259] It has been observed that, taking into account local flow velocity and the desired frequency range to be impeded, blades of commercial airliners, civil aircraft, drones, and helicopters will have multiple protrusions and valleys with a size / chord ratio similar to that of modern wind turbines.

[0260] The configuration of the structure described above for traversing a fluid environment may be used in combination with one or more of the configurations disclosed in co-pending PCT patent application No. PCT / CA2015 / / 050740 entitled “STRUCTURE WITH RIGID WINGLETADAPTED TO TRAVERSE A FLUID ENVIRONMENT” filed on the same date by Ryan Church (the contents of which are incorporated herein by reference), or in co-pending PCT patent application No. PCT / CA2015 / 050739 entitled “FLUID-REDIRECTING STRUCTURE” filed on the same date by Ryan Church (the contents of which are incorporated herein by reference).

[0261] Although embodiments have been described in detail, it should be understood that various changes, substitutions, and modifications can be made herein without departing from the scope. Furthermore, the scope of this application is not intended to be limited to the specific embodiments of the processes, machines, manufactures, material compositions, components, methods, and steps described in this specification.

[0262] As will be readily understood by those skilled in the art from this disclosure, existing or later-developed processes, machines, manufactures, material compositions, components, methods, or steps that perform substantially the same functions as those in the corresponding embodiments described herein or achieve substantially the same results as those in the corresponding embodiments described herein can be utilized. Therefore, the appended claims are intended to include such processes, machines, manufactures, material compositions, components, methods, or steps within their scope.

[0263] As you can understand, the examples described and shown above are intended to be illustrative only.

[0264] Wind tunnel details: Recently, a blade profile with a chord length of 914 mm was tested in an aeroacoustic wind tunnel at three wind speeds: 30 m / s, 50 m / s, and 70 m / s. The profile was tested with and without spoiler strips to simulate real-world turbulent wind conditions.

[0265] An example of structure 200 with d' = 191 mm, d” = 7.5 mm, w' = 41 mm, and w” = 41 mm was applied to the trailing edge of the profile and tested at different angles of attack between + / - 15 degrees. The results from the tests indicate that the average sound power level decreased to approximately 8 dB(A).

[0266] Following this, field tests were conducted, placing a variant structure 200 with sections 200A, 200B, 200C, 200D, 200E, and 200F, comprising d', d”, w', and w”, on the trailing edge of a wind turbine blade. Noise test results demonstrated industrial applicability and the practicality of the proposed method, as evidenced by a significant reduction in visible noise.

Claims

1. A group of protrusions, said protrusions being coupled to or forming part of a wing and adapted to correct the audible noise output of said wing, said protrusions comprising: Multiple adjacent protrusions and one or more valleys located between adjacent protrusions, each of the one or more protrusions having two or more peaks and an intermediate valley located between the two or more peaks; The distance (d') between the lowest point in the middle and the lowest point of one or more valleys located between adjacent protrusions is determined as at least the relationship between sound speed, boundary displacement layer thickness and total local wind speed.

2. The group of protrusions according to claim 1, wherein d' is determined without considering the highest points of the two or more peaks.

3. The protrusion assembly according to claim 1, wherein the sound velocity is determined based on the operating temperature.

4. The set of protrusions according to claim 1, wherein the two or more peaks comprise only two peaks, and the width (w') between the two peaks is determined as a relationship between at least d' and the dominant frequency to be reduced.

5. The protrusion group according to claim 1, wherein d' varies in different areas of the wing and is within 5% to 45% of the chord length of the wing, and more preferably between 15% and 25%.

6. The group of protrusions according to claim 1, wherein the plurality of protrusions are further adapted to modify the aerodynamic performance of the wing by any change in any combination of changes to d', d”, w', w”, or thereby deviate or rotate the peak away from the centerline of the base section, or thereby impart beneficial aerodynamic advantages.

7. The protrusion group of claim 5, wherein the wing is spatially divided into a plurality of separate portions, each portion having an approximate boundary displacement layer thickness, and wherein the protrusions in the protrusion group have d', the d' being determined based on the approximate boundary displacement layer thickness corresponding to the portion of the plurality of separate portions that is connected to or forms part of the protrusion.

8. The protrusion group according to claim 5, wherein the protrusions in the protrusion group have d', the d' being determined based on the thickness of a specific boundary displacement layer corresponding to the region of the wing that is connected to or forms part of the protrusion.

9. The protrusion assembly of claim 1, wherein during operation, the protrusion assembly extends beyond the trailing edge of the wing at an angle of (+ / -) 6 degrees relative to the centerline of the base section.

10. The protrusion group according to claim 1, wherein the two or more peaks and the intermediate valley are manufactured by a progressive beveling process or an injection molding process.

11. The protrusion assembly according to claim 1, wherein the protrusion assembly is modified and attached to the wing.

12. The protrusion assembly according to claim 1, wherein the wing is mounted on at least one of the following: a wind turbine, a tidal turbine, an aircraft wing, a drone rotor, or a marine wing.

13. The protrusion assembly of claim 1, wherein the correction of the audible noise output comprises generating destructive interference at human audible sound frequencies.

14. The protrusion assembly of claim 1, wherein the correction of the audible noise output comprises generating noise oriented to the frequency of the animal's audible sound.

15. The protrusion group according to claim 5, wherein the wing includes a first group of regions adapted to generate destructive interference at human audible sound frequencies and a second group of regions adapted to generate noise oriented towards animal audible sound frequencies.

16. The protrusion group of claim 15, wherein the second group region is located in the distal region of the wing relative to the root of the wing.

17. The group of protrusions according to claim 14, wherein the audible sound frequency of the animal is approximately 20-80 kHz.

18. The protrusion assembly of claim 17, wherein the animal-audible sound frequency is selected to block at least one of birds, bats, and insects.

19. The protrusion group of claim 15, wherein the correction of the audible noise output includes dynamically adjusting a controllable portion of the protrusion group to correct the distance d' in at least one of the first group region and the second group region.

20. The group of protrusions according to claim 1, wherein d' is determined using the following relationship:

21. The protrusion group according to claim 20, wherein Us is determined based on the average operating temperature in a specific operating zone.

22. The group of protrusions according to claim 4, wherein w' is determined using the following relationship:

23. The protrusion assembly of claim 1, wherein the protrusion assembly is manufactured using at least one of the following: injection molding, resin injection, laser or waterjet cutting, and 3D printing. According to claim 22, the manufacturing method thereby includes applying a surface texture to the protrusion itself or to a mold.

24. A structure for an airfoil designed to pass through a fluid medium, the airfoil having a root end, a tip end, a pressure side, a suction side, a leading edge and a trailing edge separated by a chord length, through at least a portion of the trailing edge of such an airfoil, the fluid medium being adapted to be transferred from the leading edge to the trailing edge, the structure comprising a plurality of alternating protrusions and valleys extending parallel to the chord length and through the trailing edge, the geometry of such alternating protrusions and valleys being designed to interoperate to reduce sound surges from the trailing edge of the airfoil by at least one of a local chordal spatial relationship and / or a local radial spatial relationship between two adjacent alternating valleys.

25. The structure according to claim 24, wherein the local chordal spatial relationship between the two adjacent alternating valleys is controlled by the following formula: in: d' = distance between valleys U s =Speed ​​of sound U L =Total local wind speed The alternating bulges and valleys therein achieve a target sound frequency by optimizing d' given the following inputs: the sound velocity (U) given the operating temperature. s The boundary displacement thickness (δ) BL ) and the total local wind speed (U) L ).

26. The structure according to claim 24, wherein the local radial spatial relationship between the two adjacent alternating valleys is controlled by the following formula: in: f = Dominant frequency The alternating peaks and valleys therein achieve a target sound frequency by optimizing w' given the following inputs: the speed of sound (U) given the operating temperature. s The boundary displacement thickness (δ) BL ) and the total local wind speed (U) L ).

27. The structure according to any one of claims 24 to 26, wherein the alternating protrusions and valleys have a three-dimensional geometry having a pressure side and a suction side, the geometry on both sides being inclined from the midpoint to the outer edge.

28. The structure according to any one of claims 24 to 27, wherein the alternating protrusions and valleys include a base segment designed to be attached to the trailing edge of the wing on the pressure side or suction side, the three-dimensional geometry of the base segment being obliquely cut or having tabs to integrate with the trailing edge of the wing.

29. The structure according to any one of claims 24 to 28, wherein, As measured from the edge of the base section, moving along the trailing edge of the wing from the root to the tip, the distance between the edge of the base section and each primary valley is the same, and the distance between the edge of the base section and each secondary valley gradually decreases, such that the length of the chord distance d' between the primary valley and the secondary valley gradually decreases.

30. The structure according to any one of claims 24 to 28, wherein, As measured from the edge of the base section, moving along the trailing edge of the wing from the root to the tip, the distance between the edge of the base section and each primary peak gradually decreases compared to the previous primary peak, and the distance between the edge of the base section and each secondary peak gradually decreases compared to the previous secondary peak.

31. The structure of claim 30, wherein the base section has a wavy or serrated geometry.

32. The structure of claim 30, wherein a pre-cut strip containing a wavy or serrated geometry is attached to the edge of the base section and the surface of the wing.

33. The structure according to claim 30, wherein, As measured from the edge of the basal segment, the length of each secondary peak is the same as the length of its corresponding adjacent primary peak.

34. The structure according to any one of claims 24 to 33, wherein the local radial spatial relationship w' between the two adjacent alternating valleys along the trailing edge of the wing from the root to the tip remains the same for any two adjacent alternating valleys.

35. The structure according to claim 34, wherein there are multiple segments or groups of alternating protrusions and valleys on the wing, such that the local radial spatial relationship w' between two adjacent alternating valleys remains the same for the segments or groups.

36. The structure according to claims 24 to 35, wherein the alternating protrusions and valleys are pointed.

37. The structure according to claims 24 to 36, wherein the alternating protrusions and valleys are rounded.

38. The structure according to claim 24, wherein the two or more alternating valleys contain slight depressions on the pressure side and slight depressions on the suction side, the depressions being diagonally opposite each other to induce vortex phenomena that improve the aerodynamic quality of the wing, operating alone or in combination with other wings in the system.

39. A method of attaching a series of alternating protrusions and valleys to the trailing edge of the wing according to any one of claims 24 to 38, thereby applying the attachment using fasteners or adhesives on the base section.

40. A method of attaching a series of alternating protrusions and valleys to the trailing edge of a wing according to any one of claims 24 to 39, wherein the application is performed using a clamp or multifaceted structure that attaches a base segment to the pressure side and / or suction side of the trailing edge of the wing.

41. The method according to any one of claims 24 to 40, wherein the alternating protrusions and valleys are applied after the turbine is erected.

42. The method according to any one of claims 24 to 41, wherein the alternating protrusions and valleys are applied before the turbine is erected.

43. The method according to claim 41 or 42, wherein the structure is used to enhance the control parameters of the turbine to generate additional power output or reduce noise emissions.

44. The method of claim 43, wherein the features of the enhanced control strategy are used for the refurbishment of wind turbines, the upgrading of wind turbines, or the creation of optimized control modes that can be used to optimize power, noise, and load production.

45. The method according to any one of claims 24 to 44, wherein the alternating protrusions and valleys of the structure contain recesses in the base section, the recesses being integral with the structure or additional parts of the structure for aligning the structure for placement and alignment on the trailing edge of the wing.

46. ​​The method according to any one of claims 24 to 45, wherein the alternating protrusions and valleys are integrally formed with the trailing edge of the blade during manufacturing and form an integrated portion of the suction-side and / or pressure-side shell structure.

47. A method for manufacturing a structure of alternating protrusions and valleys as described in any of the preceding claims, wherein the structure is made using injection molding.

48. A method for manufacturing a structure of alternating protrusions and valleys as described in any of the preceding structural claims, wherein the structure is made using 3D printing.

49. A method for manufacturing a structure of alternating protrusions and valleys as described in any of the preceding claims, wherein the structure is made using laser or waterjet cutting.

50. A method for manufacturing a structure of alternating protrusions and valleys as described in any of the preceding claims, wherein the structure is made of a solid or porous material.

51. The alternating protrusions structure according to any one of the preceding structural claims, wherein the wing is a wind turbine blade, a drone rotor, an aircraft wing, a propeller, a cooling fan, etc.

52. The protrusion assembly of claim 8, wherein the protrusion assembly is made of a flexible material and the protrusion assembly bends during operation to produce an angle of (+ / -) 6 degrees relative to the centerline of the base section during operation.

53. The protrusion group according to claim 1, wherein the height distance d” between the first peak and the second peak is selected to reduce swirl.

54. The protrusion group according to claim 1, wherein the radial distance w' between the primary valley and the adjacent secondary valley is determined based on the distance d' and the dominant frequency to be reduced.

55. The set of protrusions according to claim 1, wherein the radial distance w' between the primary valley and the adjacent secondary valley is determined based on the desired amount of sound attenuation.

56. The protrusion group according to claim 1, wherein the radial distance w” between the first peak and the second peak is determined based on the amount of desired sound attenuation.

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