Method for optimizing wind turbine blade assembly comprising wind turbine blade and aerodynamic attachment

Abstract

The present disclosure relates to a wind turbine blade assembly comprising a wind turbine blade and a plurality of aerodynamic appendages. The aerodynamic appendages may be asymmetrically disposed on the suction and pressure sides of the blade. The aerodynamic appendages may include a plurality of different types of appendages. The disclosure also relates to a computer-implemented method for determining a configuration of a wind turbine blade assembly comprising a wind turbine blade and a plurality of aerodynamic appendages, as well as to a data processing system and a computer program configured to perform such a method.

Description

This application claims priority to EP application No. 22211891.1, filed on December 8, 2022. Technical Field

[0001] The present disclosure relates to wind turbine blades and methods for optimizing wind turbine blades and segments of wind turbine blades. The present disclosure particularly relates to methods and systems for optimizing wind turbine blades considering noise constraints. Background Art

[0002] Modern wind turbines are often used to supply electricity to the power grid. This type of wind turbine generally includes a tower and a rotor disposed on the tower. The rotor (which typically includes a hub and multiple blades) is configured to rotate under the influence of wind on the blades. This rotation generates torque, which is typically transmitted directly (in the case of a "direct drive" or "gearless" wind turbine) or through the use of a gearbox via a rotor shaft to a generator. In this way, the generator generates electricity, which can be supplied to the power grid.

[0003] The wind turbine hub can be rotatably coupled to the front of the nacelle. The wind turbine hub can be connected to the rotor shaft, and the rotor shaft can then be rotatably mounted in the nacelle (using one or more rotor shaft bearings in a frame disposed inside the nacelle). The nacelle is a housing disposed on top of the wind turbine tower, which can contain and protect the gearbox (if present) and the generator (if not placed outside the nacelle) as well as (depending on the wind turbine) additional components and auxiliary systems such as power converters.

[0004] A wind turbine can be designed considering the average wind speed and the average wind speed distribution. Based on such average wind speed (distribution), a wind turbine can be designed considering a specific rated ("nominal") power, a specific rated ("nominal") rotational speed, and a certain rotor diameter. Based on such a nominal design of the wind turbine, the blades of the wind turbine can be designed and developed.

[0005] Given the wind speed distribution, rotor speed, rotor diameter, and nominal power, the aerodynamic properties of the blade in terms of lift and drag, etc., can be determined, which can generate a desired airfoil distribution along the length of the blade. Further inputs to the design can be the expected operating life of the wind turbine, e.g., 20 years. Considering the constraints in terms of the loads that must be withstood throughout the operating life, the design of the blade can be further optimized. The focus of wind turbine blade developers in this regard can be to minimize the cost for a given performance.

[0006] The result of the optimization process may be a blade that meets the expected performance in terms of aerodynamics, operation, mass, and load and has the lowest cost. In particular, the levelized cost of energy (LCOE) is a metric that can be considered by wind turbine and wind turbine blade developers. The LCOE is a measure of the average net present cost of electricity generation over the service life of a generator. It can be used for investment planning and for comparing different methods of electricity generation. There are different methods for determining the LCOE, and different inputs can be considered (depending on which method is used). The inputs can include capital costs, decommissioning, fuel costs, fixed and variable operation and maintenance costs, financing costs, and assumed utilization rates.

[0007] However, in practice, the wind speed distribution is not the same at all locations. In addition, in some locations or countries, specific noise constraints may exist, or noise generation may be penalized. Therefore, the wind turbine may be operated differently than initially expected, resulting in different loads and performance different from the expected performance of the blade. In addition, the same wind turbine blade can be used on different wind turbine designs.

[0008] Therefore, even if wind turbine blade manufacturers have gone through a meticulous design optimization process, the blade design may and generally will inevitably be sub-optimal in at least some implementations. However, in practice, it is not possible to develop new (optimized) wind turbine blades for every market or condition in which it can be used or even for every new wind turbine design. In addition to the time and cost involved in the development of new blades, the manufacturing of new molds for new optimized designs would be prohibitively expensive.

[0009] This disclosure provides examples of improved wind turbine blades, as well as methods and systems for optimizing wind turbine blades that take into account specific design constraints such as, for example, noise or load or improved power output. SUMMARY OF THE INVENTION

[0010] In one aspect of the present disclosure, there is provided a wind turbine blade assembly. The wind turbine blade assembly includes a wind turbine blade that extends in a longitudinal direction between a blade root and a blade tip, and the wind turbine blade has a leading edge, a trailing edge, and a pressure side and a suction side. The assembly further includes: a plurality of aerodynamic add-ons of a first type disposed on the pressure side and extending from a first longitudinal position to a second longitudinal position; and a plurality of aerodynamic add-ons of the first type disposed on the suction side and extending from a third longitudinal position to a fourth longitudinal position. Here, the third longitudinal position does not coincide with the first longitudinal position, and / or the fourth longitudinal position does not coincide with the second longitudinal position.

[0011] According to this aspect, improved performance is provided to a wind turbine blade assembly, for example in terms of aerodynamic performance (lift, drag, moment, or others) or in terms of noise. It has been found that improved performance can be achieved by abandoning the implicit design constraint of providing aerodynamic add-ons on both the suction side and the pressure side of the blade (while providing aerodynamic add-ons asymmetrically on the suction side relative to the pressure side of the blade).

[0012] In another aspect, a computer-implemented method is provided for determining the configuration of a wind turbine blade assembly including a wind turbine blade and a plurality of aerodynamic add-ons. The method includes: receiving one or more design constraints, receiving a wind speed distribution, determining a virtual model for a base design of the wind turbine blade, and determining a plurality of blade segments, where the blade segments correspond to portions of the wind turbine blade extending in the spanwise direction.

[0013] The method further includes: a) selecting one or more of the blade segments for modification; b) generating an updated virtual blade assembly by changing the configuration of virtual aerodynamic add-ons in one or more of the selected blade segments, where the virtual aerodynamic add-ons are selected from a virtual library; and c) determining the performance of the updated virtual blade assembly according to the wind speed distribution by calculating an objective function.

[0014] The method further includes: optimizing the objective function by repeating steps a)-c) until a convergence criterion has been met, while adhering to the design constraints.

[0015] The method according to this aspect recognizes that any wind turbine blade design will not be optimal for different markets, different wind speed distributions, or different noise requirements. The method also recognizes that it would be impossible to provide new molds for the blade housing for each application with slightly or moderately different requirements. The design of the wind turbine blade can still be improved or optimized for new conditions by including aerodynamic add-ons. According to this aspect, a method is provided that can effectively determine which aerodynamic add-ons can be used on the blade and at which locations to improve the performance of the blade assembly (for a specific application).

[0016] In another aspect, a data processing system is provided that is configured to execute such a method. In yet another aspect, a computer program is provided that includes instructions that cause the computer to execute such a method when the program is executed by the computer.

[0017] And in a further aspect, there is provided a computer-readable data carrier on which such a computer program has been stored. In yet a further aspect, there is provided a data carrier signal carrying such a computer program.

[0018] In yet another aspect of the present disclosure, there is provided a wind turbine blade assembly comprising: a wind turbine blade extending in a longitudinal direction between a blade root and a blade tip, the wind turbine blade having a leading edge, a trailing edge, and a pressure side and a suction side; a plurality of aerodynamic appendages of a first type arranged on the pressure side and extending from a first longitudinal position to a second longitudinal position; and a plurality of aerodynamic appendages of a second type different from the first type arranged on the suction side and extending from the first longitudinal position to the second longitudinal position.

[0019] In optimizing a wind turbine blade assembly for different objectives (in particular reducing noise, increasing lift or aerodynamic efficiency for a given wind speed), it has been found that an asymmetric distribution of aerodynamic appendages can be beneficial.

[0020] In a further aspect, there is provided a wind turbine blade assembly. The wind turbine blade assembly includes a wind turbine blade extending in a longitudinal direction between a blade root and a blade tip, and the wind turbine blade having a leading edge, a trailing edge, and a pressure side and a suction side. The assembly further includes: a plurality of aerodynamic appendages arranged on the pressure side and extending from a first longitudinal position to a second longitudinal position; and a plurality of aerodynamic appendages arranged on the suction side and extending from a third longitudinal position to a fourth longitudinal position; and wherein the first, second, third, and fourth positions are arranged in the outer half of the wind turbine blade, and wherein the third longitudinal position does not coincide with the first longitudinal position, and / or the fourth longitudinal position does not coincide with the second longitudinal position.

[0021] In yet a further aspect, there is provided a wind turbine blade assembly. The wind turbine blade assembly includes a wind turbine blade extending in a longitudinal direction between a blade root and a blade tip, and the wind turbine blade having a leading edge, a trailing edge, and a pressure side and a suction side. The assembly further includes trailing edge serrations along the trailing edge from a first longitudinal position to a second longitudinal position, wherein a plurality of aerodynamic appendages are arranged on the pressure side between the first and second longitudinal positions, and a plurality of aerodynamic appendages are arranged on the suction side between the first and second longitudinal positions. The arrangement of the aerodynamic appendages on the pressure side between the first and second longitudinal positions is different from the arrangement of the aerodynamic appendages on the suction side.

[0022] In yet another aspect, the present disclosure provides a wind turbine blade assembly including a wind turbine blade extending longitudinally between a blade root and a blade tip, and having a leading edge, a trailing edge, and a pressure side and a suction side. The blade assembly further includes trailing edge serrations extending from a first longitudinal position to a second longitudinal position, and includes no trailing edge serrations between the second longitudinal position and a third longitudinal position, and further includes trailing edge serrations extending from the third longitudinal position to a fourth longitudinal position.

[0023] In yet a further aspect, the present disclosure provides a wind turbine blade assembly including a wind turbine blade extending longitudinally between a blade root and a blade tip, and having a leading edge, a trailing edge, and a pressure side and a suction side. The blade assembly further includes: a first plurality of aerodynamic add-ons disposed on the pressure side and extending from a first longitudinal position to a second longitudinal position; and a second plurality of aerodynamic add-ons disposed on the suction side and extending from the first longitudinal position to the second longitudinal position. The blade assembly further includes trailing edge serrations along the trailing edge from the first longitudinal position to the second longitudinal position. The blade assembly further includes: a third plurality of aerodynamic add-ons disposed on the pressure side between a third longitudinal position and a fourth longitudinal position; and a fourth plurality of aerodynamic add-ons disposed on the suction side between the third longitudinal position and the fourth longitudinal position, wherein no trailing edge serrations are provided between the third and fourth longitudinal positions.

[0024] The various aspects disclosed herein may also be combined.

[0025] Throughout the present disclosure, aerodynamic add-ons may be regarded as elements or components added to a wind turbine blade to affect and specifically enhance its aerodynamic properties. They may be regarded as added to the blade because they are not integrated into the blade during the blade mold manufacturing process. Aerodynamic add-ons may be attached to the outer surface of the wind turbine blade to improve the power generation of the blade (or the wind turbine including the blade), to reduce the noise level of the blade, and / or to adapt the aerodynamic properties of the blade in some way. Often, these blade add-ons may protrude from the blade surface (i.e., the suction surface or the pressure surface).

[0026] Throughout the present disclosure, an aerodynamic add-on is designated as a different type of add-on when it has a different objective from another add-on and / or is based on another aerodynamic principle different from that of another add-on. Additionally, an aerodynamic add-on may be a different type of add-on even if its operation is based on the same aerodynamic principle but it has a significantly different size compared to another aerodynamic add-on. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 Perspective view of an example of a wind turbine shown;

[0028] Figure 2A Perspective view of an example of a wind turbine blade shown;

[0029] Figure 2B Schematic illustration of the internal structure of a wind turbine blade;

[0030] Figure 2C Schematic illustration of an example of a wind turbine blade assembly including a plurality of aerodynamic add-ons;

[0031] Figure 3 Schematic illustration of an example of a method for determining the configuration of a wind turbine blade assembly;

[0032] Figure 4A and Figure 4B Schematic illustration of two aerodynamic add-ons and some of the parameters that can be varied with respect to these add-ons;

[0033] Figures 5A - 5D Schematic illustration of how blade assemblies using the same standard blade design can be optimized differently depending on specific goals and / or constraints in different implementations; and

[0034] Figures 6A - 6D Schematic illustration of an example of a wind turbine blade assembly according to the present disclosure. DETAILED DESCRIPTION

[0035] Reference will now be made in detail to embodiments of the present disclosure, one or more examples of which are illustrated in the accompanying drawings. Each example is provided by way of explanation only and not limitation. In fact, it will be apparent to those skilled in the art that various modifications and variations can be made in the present disclosure. For example, features illustrated or described as part of one embodiment can be used with another embodiment to yield still another embodiment. Accordingly, it is intended that the present disclosure cover such modifications and variations as fall within the scope of the appended claims and their equivalents.

[0036] Figure 1 An illustration of a conventional modern upwind wind turbine 2 according to the so-called "Danish concept", which has a tower 4, a nacelle 6 and a rotor with a substantially horizontal rotor shaft. The rotor includes a hub 8 and three blades 10 that extend radially from the hub 8, each having a blade root 16 closest to the hub and a blade tip 14 furthest from the hub 8.

[0037] Figure 2AA schematic view showing an exemplary wind turbine blade 10 is presented. The wind turbine blade 10 has the shape of a conventional wind turbine blade with a root end 17 and a tip 15, and includes a root region 16 closest to the hub, an airfoil or profile region 34 farthest from the hub, and a transition region 32 between the root region 16 and the airfoil region 34. The blade 10 includes a leading edge 18 that faces the direction of rotation of the blade 10 when the blade is mounted on the hub; and a trailing edge 20 that faces the opposite direction of the leading edge 18.

[0038] The airfoil region 34 (also known as the profile region) has an ideal or nearly ideal blade shape for generating lift, while the root region 16 (due to structural considerations) has a substantially circular or elliptical cross-section, which, for example, makes it easier and safer to mount the blade 10 to the hub. The diameter (or chord) of the root region 16 can be constant along the entire root region 16. The transition region 32 has a transition profile that gradually changes from the circular or elliptical shape of the root region 16 to the airfoil profile of the airfoil region 34. The chord length of the transition region 32 generally increases with the increasing distance from the hub. The airfoil region 34 has an airfoil profile, where the chord extends between the leading edge 18 and the trailing edge 20 of the blade 10. The width of the chord decreases with the increasing distance from the hub.

[0039] The shoulder 40 of the blade 10 is defined as the location where the blade 10 has its maximum chord length. The shoulder 40 is typically provided at the boundary between the transition region 32 and the airfoil region 34.

[0040] It should be noted that the chords of the different segments of the blade generally do not lie in a common plane, and since the blade may be twisted and / or bent (i.e., pre-bent), it is most common to provide a corresponding twisted and / or bent path for the chord plane in order to compensate for the local speed of the blade depending on the radius from the hub.

[0041] The wind turbine blade 10 includes a blade shell, which includes two blade shell parts or half-shells, namely, a first blade shell part 24 and a second blade shell part 26, typically made of fiber-reinforced polymer. The wind turbine blade 10 may include additional shell parts, such as a third shell part and / or a fourth shell part. The first blade shell part 24 is typically the pressure side or upwind blade shell part. The second blade shell part 26 is typically the suction side or downwind blade shell part. The first blade shell part 24 and the second blade shell part 26 are fastened together along a joint line or glue joint 28 (which extends along the trailing edge 20 and the leading edge 18 of the blade 10) with an adhesive such as glue. Generally, the root ends of the blade shell parts 24, 26 have a semi-circular outer cross-sectional shape.

[0042] Figure 2BIt is a schematic view of a cross-sectional view of an exemplary wind turbine blade 10 (e.g., the airfoil region 34 of the wind turbine blade 10). The wind turbine blade 10 includes a leading edge 18, a trailing edge 20, a pressure side 24, a suction side 26, a first beam cap 74, and a second beam cap 76. The wind turbine blade 10 includes a chord line 38 between the leading edge 18 and the trailing edge 20. The wind turbine blade 10 includes shear webs 42, such as a leading edge shear web and a trailing edge shear web. The shear web 42 may alternatively be a beam box having beam sides (such as a trailing edge beam side and a leading edge beam side, etc.). The beam caps 74, 76 may include carbon fiber, while the remaining parts of the shell portions 24, 26 may include glass fiber.

[0043] Figure 2C The schematic view shows an example of a wind turbine blade assembly 110. The wind turbine blade assembly 110 includes a wind turbine blade 10, and the wind turbine blade 10 has Figure 2A the shape of a conventional wind turbine blade with a root end 17 and a tip 15 as shown in the figure, and includes a root region 16 closest to the hub, an outer shape or airfoil region 34 farthest from the hub, and a transition region 32 between the root region 30 and the airfoil region 34. The blade 10 includes: a leading edge 18 that faces the direction of rotation of the blade 10 when the blade is mounted on the hub; and a trailing edge 20 that faces the opposite direction of the leading edge 18. Figure 2A The description of the wind turbine blade 10 generally applies to Figure 2C examples of the blades.

[0044] The wind turbine blade assembly 110 includes a plurality of noise reduction elements 48. For example, it includes a first noise reduction element 50 and a second noise reduction element 90, which are attached and distributed along the trailing edge 20 of the wind turbine blade 10. The first noise reduction element 50 includes a first serrated portion.

[0045] Each of the plurality of noise reduction elements 48 includes a base portion 60. The base portion 60 of each of the plurality of noise reduction elements 48 can be attached to the trailing edge 20 of the wind turbine blade, such as being attached to the suction side 26 or the pressure side 24 near the trailing edge 20. The plurality of noise reduction elements 48 can be distributed along the entire length of the trailing edge 20, or the plurality of noise reduction elements 48 can be distributed along a portion of the length of the trailing edge 20 starting from the tip 15.

[0046] Figure 3The schematic diagram illustrates an example of a computer - implemented method 100 for determining the configuration of a wind turbine blade assembly including a wind turbine blade and a plurality of aerodynamic add - ons. The method includes receiving, at block 115, one or more design constraints and receiving, at block 120, a wind speed distribution. The method also includes determining, at block 130, a virtual model of a base design of the wind turbine blade and determining, at block 140, a plurality of blade segments, where the blade segments correspond to portions of the wind turbine blade extending in the spanwise direction.

[0047] The method also includes selecting, at block 150, one or more of the blade segments for modification and generating, at block 160, an updated virtual blade assembly by changing the configuration of virtual aerodynamic add - ons in one or more of the selected blade segments. The virtual aerodynamic add - ons are selected from a virtual library 165.

[0048] The method then includes, at block 170, determining the performance of the virtual blade assembly based on the wind speed distribution by calculating an objective function.

[0049] Method 100 also includes optimizing the objective function by repeating the steps of blocks 150 - 170 until a convergence criterion has been met while adhering to the design constraints.

[0050] Even though method 100 has been described in Figure 3 a particular sequence of steps, the sequence of steps should not be construed as limiting. The order of several steps can be changed. By way of example only, the order of steps 115, 120, 130, and 140 can be freely interchanged.

[0051] Some of the steps of method 100 will now be described in more detail, as well as some implementations of method 100 and different possible implementations of the individual steps.

[0052] In some examples, the design constraints can include the maximum load on the wind turbine blade assembly. Additional design constraints may include blade mass not to be exceeded, cut - in and cut - out wind speeds, specific market requirements, noise constraints, and others. The design constraints received at block 115 form one of the basic inputs for a later optimization process. Only when the design constraints are satisfied can an improved or optimal design of the objective function for the wind turbine blade assembly be acceptable. The design constraints can be received from user input through a suitable user interface.

[0053] Another basic input for the optimization process is received at block 120, namely, the wind speed distribution. The wind speed distribution can be defined in a variety of ways, but will generally define the average or median wind speed and may also include the probability distribution of other wind speeds within the cut-in and cut-out wind speeds. The wind speed distribution can be used to examine the performance of different potential configurations of the aerodynamic add-ons.

[0054] The wind speed distribution can be or include an effective wind speed distribution. That is, how the operation of the wind turbine and the pitch angle and rotor speed vary as a function of the free stream wind speed can be considered. The effective wind force experienced by a segment or part of a blade will depend not only on the free stream wind speed but also on the operation of the turbine.

[0055] The wind speed distribution can be received from user input via an available interface. In other examples, the wind speed distribution can be downloaded from a database containing wind power data for different locations. The wind speed distribution, especially the effective wind speed distribution, can also be calculated by combining user inputs from different sources.

[0056] At block 130, a virtual model of the basic design of the blade can be determined. The basic design of the blade can specifically include the airfoil distribution over the span of the blade.

[0057] The basic design of the blade forms the starting point for further optimization and can correspond to the blade design without any aerodynamic add-ons or with one or more aerodynamic add-ons that are considered to be the default design. The basic design itself can be part of a design process that takes into account a certain theoretical wind speed distribution and theoretical wind turbine requirements (in terms of rotor speed, nominal power, etc.). This theoretical wind speed distribution and theoretical requirements may be slightly or significantly different from the actual requirements for a particular wind turbine model or at a particular wind site in practice. These actual requirements are collected as described previously at blocks 115 and 120.

[0058] The virtual blade design can be divided into a plurality of blade segments at block 140. The blade segments correspond to portions of the wind turbine blade that extend in the spanwise direction. They can have, for example, a constant length of approximately 1 meter, or they can have a length that varies along the blade span, for example, approximately 1 meter in the middle of the blade and, for example, approximately 0.5 meter closer to the tip. Dividing into blade segments at block 140 makes it possible to calculate the performance of each of the individual blade segments separately.

[0059] A blade section can be determined in the following way: Assuming a constant cross-section, constant wind speed, and angle of attack, the performance of an individual blade section can be determined with sufficient reliability. During the operation of a wind turbine, depending on the wind speed and rotational speed, each section of the blade will experience a different effective wind speed. Additionally, the angle of attack of an individual section can vary along the blade span. The angle of attack for a certain part of a wind turbine blade is a function of the pitch angle (usually specified by the turbine operation), the free-stream wind speed, the rotor speed (usually specified by the turbine operation), the longitudinal position of the part along the blade span, and the local twist angle. Thus, a blade section can be determined in the following way: The cross-sectional shape of the section can be assumed to be constant, and the operating conditions (effective wind speed, angle of attack) can be assumed to be constant.

[0060] Blocks 150 - 170 can be repeated until an "optimal" blade assembly layout has been found for a particular implementation. The optimal that can be found can depend particularly on the objective function to be optimized.

[0061] In some examples, the objective function includes the performance of the blade with respect to noise. In some examples, the objective function includes the power output of the wind turbine. In an example, the objective function can include the performance of the blade with respect to noise and power output. The performance with respect to noise can affect the operation of the wind turbine and thus the power output.

[0062] In some examples, the objective function can be the calculation of the levelized cost of energy (LOCE). Such an objective function can take into account both the power output and noise constraints (e.g., as a penalty affecting the power output, or as a (virtual) increase in the power output for each dB of noise reduction). If the LCOE or some other objective function considering the cost of the blade assembly is used, then for each of the available blade add-ons, information about the cost of the add-on can be included in the calculation. Such costs can include one or more of the manufacturing or procurement cost, the assembly cost, and the maintenance cost.

[0063] In each iteration, one or more blade sections can be modified. Add-ons can be added to the blade section, or can be removed from the virtual blade section. The position of the add-on can be changed, e.g., the add-on can be positioned differently in the chordwise direction, and the add-on can be arranged on the suction side and / or the pressure side. Depending on the situation, such modifications can be made on the pressure side, on the suction side, or on both.

[0064] After such modifications, the performance of the updated virtual blade assembly according to the wind speed distribution can be calculated using the defined objective function. In an example, this can include determining the performance of the virtual blade assembly by calculating the performance of a plurality of individual blade sections. That is, the overall performance of the blade assembly is the sum or combination of the performance of the individual blade sections.

[0065] In an example, calculating the performance of multiple blade segments includes: using one or more engineering models to calculate the performance. The engineering models can be regarded as simplified mathematical models in this document, and the simplified mathematical models include equations or systems of equations to approximately calculate the performance of blade segments in a specific combination of situations. For a given effective wind speed and a given angle of attack, the aerodynamic performance of a blade segment (assuming a constant cross-section and a constant airfoil profile) can be calculated relatively quickly. If one or more aerodynamic add-ons are added to such a blade segment, the performance of the blade segment is significantly changed, but the performance can be estimated or approximately calculated using the (simplified) theoretical behavior of the add-ons. Such engineering models can be determined based on experimental wind field data and wind tunnel data. Such engineering models can also be derived as analytical models for solving (one or more) physical equations or as simplified analytical models.

[0066] In a similar manner, engineering models can be used to calculate the lift, drag, loads, and noise for each blade segment.

[0067] In these examples, to find an optimal solution more quickly and / or with reduced computational power requirements, simplified calculations can be used instead of full finite element calculations for the entire blade or for blade segments. In some examples, engineering models can be used in a first set of iterations. In a second set of iterations, finite element calculations may be used to more finely tune the wind turbine blade assembly and more precisely determine its performance.

[0068] Such engineering models can also consider aeroelastic effects, that is, the engineering models can consider that: depending on the load, the blade may deform. The deformation itself will affect the aerodynamic flow around the blade assembly. Models used to calculate blade deformation and loads (including stress, bending moment, etc.) for each blade segment can include standard finite beam formulas or multi-body methods, where each body is a beam element that considers the nonlinear effects of body motion (rotation and deformation). Such structural models can be coupled with aerodynamic models assuming steady or unsteady flow, for example, considering the dynamic changes in the wind flow and the blade rotation effects, including dynamic stall and other phenomena known to those skilled in the art.

[0069] In some other examples, 2D computational fluid dynamics (CFD) may be used instead of engineering models. In still other examples, if computational power is available, 3D CFD methods can be used.

[0070] In some examples, selecting multiple virtual aerodynamic add-ons from library 165 may include multiple different virtual aerodynamic add-ons to be added to the correspondingly selected blade segments. The virtual aerodynamic add-ons can rely on different aerodynamic effects and can be add-ons of different sizes.

[0071] The library 165 of virtual add-ons may include the information required in the aforementioned engineering model. Such information may include information about cost (to the extent considered), their impact on noise, and their impact on aerodynamic performance (lift coefficient, drag coefficient, aerodynamic moment).

[0072] An example of such a virtual library including different aerodynamic add-ons is schematically depicted in the following table.

[0073] In the simplified example of the above table, only five types of aerodynamic add-ons have been included, but it will be clear that many more or also fewer types of aerodynamic add-ons can be considered. In the simplified example of the above table, qualitative characteristics have been indicated for each of the add-ons, but it will be clear that in other examples, various characteristics for each of the aerodynamic add-ons can be quantified, i.e., expressed using specific numerical values.

[0074] As mentioned previously, the engineering model can be used in iterative steps to describe the behavior of the add-ons. Such an engineering model can be defined for multiple or all of the virtual aerodynamic add-ons from the library (from which they can be selected). Since the behavior of each of the add-ons can be different, they can each have their own predefined equations describing their behavior.

[0075] As an example, the behavior of vortex generators will be based on multiple variables that form part of the design: the airfoil on which they are placed, their position along the chord, the spacing between the vortex generators, the angle formed between the vortex generators and the chord direction, etc.

[0076] This can be referred to Figure 4A and Figure 4B be illustrated. Figure 4A The leading edge protector is illustrated, and the leading edge protector (LEP) can be one of the virtual aerodynamic add-ons. The leading edge protector (LEP) can be defined by variables that include, for example, the thickness d of the LEP, the positions along the chord to which the LEP extends on the windward and leeward sides of the blade (x up and x do ). The airfoil on which the LEP can be mounted can be defined by x and y coordinates. The behavior of the LEP will depend on, for example, the wind force or operating conditions defined by the Mach number M and the angle of attack AoA of the airfoil (section).

[0077] The engineering model associated with the LEP can define equations for the sound / noise generation and aerodynamic behavior of the LEP (depending on the relevant variables): C L_LEP =f(airfoil[X,Y],M,AoA,d,x up, x do) Equation 1 C D_LEP = f(Airfoil[X,Y], M, AoA, d, x up, x do ) Equation 2 C M_LEP = f(Airfoil[X,Y], M, AoA, d, x up, x do ) Equation 3 L P_LEP = f(Airfoil[X,Y], M, AoA, d, x up, x do , Observer[X,Y,Z]) Equation 4

[0078] Here, Airfoil[X,Y] relates to the blade segment coordinates. C L , C D and C M relate to the lift coefficient, drag coefficient, and moment coefficient respectively. LP relates to the sound pressure level at the observer position, and Observer[X,Y,Z] defines the coordinates of the observer position where Lp is calculated. The subscript LEP indicates that these equations are defined for the leading edge protector. Similarly, the vortex generator can be defined using multiple variables as illustrated in Figure 4B . The variables defining the vortex generator in one example can include one or more of the following variables: height (h), length (l), the spacing (S) at the trailing edge between vortex generators, and the angle between the vortex generator and the chord () and their position X up and X do . These variables are illustrated in Figure 4B . It should be clear that in other examples, other variables may be used.

[0079] Similarly, the behavior of the vortex generator will also depend on wind conditions and operating conditions such as Mach number, angle of attack, etc.

[0080] The aerodynamic behavior and noise behavior of the vortex generator can be defined by multiple equations: C L_VG = f(Airfoil[X,Y], M, AoA, h, I, S, Z, b, x up, x do ) Equation 5 C D_VG = f(Airfoil[X,Y], M, AoA, h, I, S, Z, b, x up, x do ) Equation 6 C M_VG = f(Airfoil[X,Y], M, AoA, h, I, S, Z, b, x up, x do) Equation 7 L P_VG = f(Airfoil[X,Y], M, AoA, h, I, S, Z, b, x up, x do , Observer[X,Y,Z]) Equation 8

[0081] Herein, again, Airfoil[X,Y] relates to blade section coordinates. C L , C D and C M relate to the lift coefficient, drag coefficient, and moment coefficient, respectively, and L P relates to the sound pressure level at the observer location, and Observer[X,Y,Z] defines the coordinates of the observer location where Lp is calculated. The subscript VG indicates that these equations are defined for the vortex generator.

[0082] Similar equations can be defined for each of the aerodynamic add-ons defined in the virtual library to allow for quick optimization without the need for a large amount of computational power. The equations can be based on theoretical analysis models, simulations, tests, field experience, or any combination of these.

[0083] Aerodynamic add-ons that can be considered to be included in one or more blade sections of a blade section include aerodynamic add-ons configured to reduce noise (e.g., trailing edge serrations such as conical serrations, triangular serrations, fins, or others) and are add-ons of different sizes. Further, aerodynamic add-ons configured to increase the lift (coefficient) of the blade section or generally improve the aerodynamic efficiency (L / D or C L / C D ) can be considered, such as, for example, vortex generators, micro-vortex generators (which can be considered to be vortex generators that are small compared to the boundary layer of the aerodynamic flow around the blade), flaps, slats, micro-tabs, or others. Such add-ons aimed at improving aerodynamic efficiency can also include add-ons that specifically reduce drag, such as, for example, riblets or drag reduction surface treatments. Other aerodynamic add-ons can include leading edge protectors (to improve the aerodynamic flow around the blade by avoiding corrosion while noise generation can be increased) and spoilers.

[0084] Fins can be regarded as a plurality of generally parallel comb-like arrays of thin plate-like elements protruding from the pressure and / or suction side surfaces of the blade. Since the plate-like elements are arranged close to each other and extend substantially parallel to each other, the aerodynamic flow on the surface travels in a smooth parallel path. The fins can extend from approximately 65 - 80% of the local chord to the trailing edge. The fins can be provided with different spacings during and are provided with different heights. The fins can extend beyond the trailing edge of the blade in the example.

[0085] The micro - fins generally consist of small fins placed on the airfoil surface near the trailing edge and perpendicular to the surface. Generally, the micro - fins can be used on the pressure side of the blade to change the position of the air flow spacing along the pressure surface, with the goal of increasing lift.

[0086] In an example, at least two different types of virtual aerodynamic add - ons can be selected from a library.

[0087] Different algorithms can be used to optimize the objective function and perform iterations until the convergence criterion has been met. In some examples, first - order or second - order optimization algorithms can be used. In other examples, population algorithms such as genetic algorithms can be used. In additional examples. In other examples, several different algorithms can be combined.

[0088] In some examples, the genetic algorithm can be used to optimize the objective function in the first set of iterations. In some examples, the optimized objective function includes using a gradient - based algorithm (e.g., a first - derivative optimization algorithm) in a second set of iterations after the first set of iterations. Combining algorithms in this way has been found to quickly lead to an improved or optimal design for a wind turbine blade assembly.

[0089] Figure 5A and Figure 5B A first example illustrating how the optimal configuration of a wind turbine blade assembly can be driven by specific requirements at a specific location. Figure 5A Illustrating the noise generation of a wind turbine blade as a function of the free - stream wind speed at hub height. The total noise generated by the wind turbine blade can be assigned to multiple different noise sources. In this example, the different noise sources can be considered as the trailing - edge suction and pressure sides, trailing - edge bluntness, inflow turbulence, and noise generated by the blade tip. It can be seen that the contribution of each of these sources is different for different wind speeds. As an example, the overall noise at a wind speed of 14 m / s is approximately the same as the overall noise at a wind speed of 9 m / s. However, the contribution of the tip to this noise is much lower at 14 m / s. On the other hand, the contribution of the trailing - edge bluntness is much higher at 14 m / s.

[0090] In Figure 5A the example, due to the specific implementation of the blade, noise generation is to be minimized at a wind speed of 9 m / s at hub height. Knowledge of which sources contribute to the noise can drive the selection of appropriate add - ons along the span of the blade. Figure 5B Illustrated by example how noise generation can vary along the span of the blade at a given wind speed (in this case 9 m / s). Such as Figure 5BThe analysis shown can be used by an (one or more) optimization algorithm in an iteration to optimize an objective function while adhering to constraints. By identifying the most important noise sources, suitable aerodynamic add-ons can be selected to reduce noise.

[0091] In a specific example, the noise generated near the tip is relatively important, and the optimization with a specific noise constraint at 9 m / s can result in a distribution of trailing edge serrations from approximately 65 or 70% of the span of the blade to the tip of the blade. In the example, from approximately 65 - 75% of the span of the blade, triangular serrations can be used, from 75% of the span to approximately 90% of the span, conical serrations can be used, and from approximately 90% of the span to approximately 100%, triangular serrations can be combined with fins provided on the suction side.

[0092] Figure 5C Another example shows different noise sources for different base designs of a wind turbine blade and their relative contributions (as a function of the free stream wind speed at hub height). In Figure 5C the example, the optimization of the blade can be selected for a specific noise reduction at a wind speed of 15 m / s.

[0093] Figure 5D The schematic shows how noise generation can vary along the span of the blade, i.e., how different blade segments can contribute to the overall noise. Considering different noise objectives, the distribution of aerodynamic add-ons may be different. Again, trailing edge serrations can be provided from approximately 65% of the span of the blade to approximately 100% of the span of the blade. However, in this example, from approximately 75% of the span of the blade to approximately 100% of the span of the blade, conical serrations can be used, and from 65% of the span to approximately 75% of the span, triangular serrations can be used. In this specific example, these serrations can be combined with, for example, fins from approximately 90 - 100% of the span of the blade on the suction side (and none on the pressure side) and fins from approximately 75 - 85% of the span of the blade on the pressure side (and none on the suction side).

[0094] Thus, it can be seen how the optimization of the examples illustrated herein can lead to different results (depending on design constraints and the objective function). It can also be seen how such optimization of aerodynamic add-ons can lead to unexpected counterintuitive results. In Figure 5D the example, it is found that, for example, fins may be provided on both the suction side and the pressure side, but they are asymmetrically distributed on both sides of the blade.

[0095] In the example, the convergence criterion can be defined such that the iteration stops when no meaningful improvement of the objective function is achieved. Once the convergence criterion has been reached, the design of the wind turbine blade assembly can be considered frozen for a specific implementation.

[0096] In an example, the method may further include: at block 190, providing a layout of the aerodynamic add-ons when a convergence criterion has been met. The release of the resulting layout may be used for manufacturing purposes.

[0097] In some examples, the method may further include at block 195 providing performance characteristics of the blades. The method may include providing one or more of the following: a noise curve of the wind turbine blade assembly as a function of wind speed, a power curve of the wind turbine as a function of wind speed, one or more loads on the wind turbine blade assembly as a function of wind speed.

[0098] In some examples, the method may further include manufacturing a wind turbine blade assembly based on a baseline design of the wind turbine blade and the provided layout of the aerodynamic add-ons. In particular, the baseline design of the wind turbine blade may include manufacturing a pressure side shell and a suction side shell with a mold and joining the shells to each other, including, for example, beam caps and shear webs. The selected aerodynamic add-ons may be manufactured separately and assembled to the wind turbine blade. The assembly with the turbine blade may be performed in a factory and / or on site (depending on the aerodynamic add-ons).

[0099] In a further aspect of the present disclosure, there is provided a wind turbine blade obtainable by any of the methods disclosed herein.

[0100] In a further aspect of the present disclosure, a computer program includes instructions which, when the program is executed by a computer, cause the computer to perform any of the examples of the optimization methods described herein. Such a computer program may be provided on a computer-readable data carrier or on a data carrier signal.

[0101] The computer program may be in the form of source code, object code, intermediate source and object code (such as in a partially compiled form) or in any other form suitable for use in the implementation of a process. The carrier may be any entity or device capable of carrying the computer program.

[0102] In still further aspects of the present disclosure, there is provided a data processing system configured to perform any example of the optimization methods described herein. Such a data processing system may include: functionality / modules for receiving one or more design constraints; functionality for receiving a wind speed distribution; functionality / modules for determining a virtual model of a basic design of a wind turbine blade; and functionality / modules for determining a plurality of blade segments, where the blade segments correspond to portions of the wind turbine blade extending in the spanwise direction. The data processing system may further include functionality / modules for: a) selecting one or more of the blade segments for modification; b) generating an updated virtual blade assembly by changing the configuration of virtual aerodynamic add-ons in one or more of the selected blade segments, where the virtual aerodynamic add-ons are selected from a virtual library; and c) determining the performance of the virtual blade assembly based on the wind speed distribution by calculating an objective function; and further for optimizing the objective function by repeating steps a)-c) until a convergence criterion has been met while adhering to the design constraints.

[0103] Examples of the methods disclosed herein may be implemented using hardware, software, firmware, and combinations thereof. Examples of the methods disclosed herein may employ one or more of virtual machines, cloud computing, and edge computing.

[0104] Those skilled in the art will further appreciate that the various illustrative logical blocks, modules, circuits, and algorithm steps described in connection with the present disclosure may be implemented as electronic hardware, computer software, or combinations of both. To clearly illustrate this interchangeability of hardware and software, the various illustrative components, blocks, modules, circuits, and steps have been described above in terms of their functional aspects. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the overall system. Skilled artisans may implement the described functionality in varying ways for each particular application.

[0105] One or more general-purpose processors, digital signal processors (DSPs), cloud computing architectures, application specific integrated circuits (ASICs), field programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein may be used to implement or execute the various illustrative logical blocks, modules, and circuits described in connection with the present disclosure. A general-purpose processor may be a microprocessor, but in the alternative, the processor may be any conventional processor, controller, microcontroller, or state machine. The processor may also be implemented as a combination of computing devices, e.g., a DSP and a microprocessor, multiple microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration.

[0106] If implemented in software / firmware, the functions may be stored on a computer-readable medium or transmitted as one or more instructions or codes on a computer-readable medium. Computer-readable media includes both computer storage media and communication media including any medium that facilitates transfer of a computer program from one place to another. The storage media may be any available media that can be accessed by a general or special purpose computer. By way of example, and not limitation, such computer-readable media can comprise RAM, ROM, EEPROM, CD / DVD or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to carry or store desired program code components in the form of instructions or data structures and that can be accessed by a general or special purpose computer or a general or special purpose processor. In addition, any connection is properly termed a computer-readable medium. For example, if the software / firmware is transmitted from a website, server, or other remote source using a coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave, then the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are included in the definition of the medium. As used herein, disk and disc include compact disc (CD), laser disc, optical disc, digital versatile disc (DVD), floppy disk, and Blu-ray disc where disks usually reproduce data magnetically, while discs reproduce data optically with lasers. Combinations of the above should also be included within the scope of computer-readable media.

[0107] Figure 6A The schematic diagram shows an example of a wind turbine assembly according to another aspect of the present disclosure. Figure 6A An example of a wind turbine blade assembly 110 is illustrated. The wind turbine blade assembly includes a wind turbine blade 10 that extends in a longitudinal direction between a blade root 17 and a blade tip 15 and the wind turbine blade 10 has a leading edge, a trailing edge, and a pressure side 24 and a suction side 26.

[0108] In Figure 6A , different blade segments are indicated as extending from a longitudinal position X1 to x2, from the longitudinal position x2 to x3, from the longitudinal position x3 to x4, and from the longitudinal position x4 to x5. Such blade segments can be used in the examples of the methods described above. Each of these blade segments can represent a degree of freedom in the optimization of the wind turbine blade assembly. It also schematically indicates that the segments near the blade tip can be smaller.

[0109] The wind turbine blade assembly 110 further includes a plurality of aerodynamic add-ons 220 of a first type, which are arranged on the pressure side 24 and extend from a first longitudinal position x1 to a second longitudinal position (here x3). The wind turbine blade assembly 110 further includes a plurality of aerodynamic add-ons 220 of a first type, which are arranged on the suction side 26 and extend from a third longitudinal position x3 to a fourth longitudinal position x4. Here, the third longitudinal position x3 does not coincide with the first longitudinal position x1, and / or the fourth longitudinal position x4 does not coincide with the second longitudinal position x2.

[0110] In other words, aerodynamic add-ons 220 of the first type are provided both on the pressure side and on the suction side, but they are asymmetrically distributed.

[0111] In this example, the third longitudinal position on the suction side does not coincide with the second longitudinal position on the pressure side, but it should be clear that this may not be the case in other examples.

[0112] In this particular example, the aerodynamic add-ons on the suction side are arranged along a portion of the blade that is radially more outward (closer to the tip) compared to the aerodynamic add-ons on the pressure side 24. In other examples, there may be an overlap between the range of positions on the pressure side 24 and the range of positions on the suction side 26.

[0113] In some examples, the wind turbine blade assembly may further include a plurality of aerodynamic add-ons 210 of a second type. In this example, the aerodynamic add-ons 210 of the second type may be trailing edge serrations. In Figure 6A the schematic diagram, trailing edge serrations are depicted both on the suction side and on the pressure side because they can be regarded as an extension of the trailing edge (which forms the boundary edge for both the suction side and the pressure side).

[0114] In some examples, the aerodynamic add-ons 210 of the second type are arranged between the first and second longitudinal positions on the pressure side and / or between the third and fourth longitudinal positions on the suction side. Thus, along a spanwise portion of the blade, both the first and second types of add-ons can be arranged. In this particular example, the add-ons of the second type extend from the first (radially innermost) longitudinal position x1 to the fourth (radially outermost) longitudinal position x4.

[0115] In some examples, the wind turbine blade assembly may further include a plurality of aerodynamic add-ons of a third type (different from the first and second types).

[0116] In some examples, the first and / or second aerodynamic add-ons may be one or more of the following: triangular trailing edge serrations, trailing edge tapered serrations, fins, vortex generators, flaps, spoilers, and microtabs.

[0117] In some examples, a first type of aerodynamic add-on (i.e., an aerodynamic add-on that is asymmetrically distributed between a pressure side and a suction side) is an add-on configured to reduce the noise of a wind turbine blade assembly in use or an add-on configured to increase lift or improve the aerodynamic efficiency of a wind turbine blade assembly in use. It has been found that, particularly for fins (for noise reduction) and vortex generators (for lift increase and drag reduction), the asymmetric distribution described herein can be beneficial.

[0118] In examples, the first, second, third, and fourth longitudinal positions can all be arranged in the outer half of the wind turbine blade, i.e., the half of the blade extending from 50 - 100% of the blade span. In some examples, the third and fourth longitudinal positions can be arranged in the outer third of the wind turbine blade, i.e., the portion of the blade extending from approximately 67% to 100% of the span.

[0119] Figure 6B The schematic diagram shows another example of a wind turbine blade assembly. The same reference numerals as in Figure 6A have been used to indicate the same elements. Figure 6B There is shown a wind turbine blade assembly 110, including: a wind turbine blade 10 that extends longitudinally between a blade root 17 and a blade tip 15; and the wind turbine blade 10 has a leading edge, a trailing edge, and a pressure side 24 and a suction side 26. A plurality of first type aerodynamic add-ons 230 are arranged on the pressure side 24, extending from a first longitudinal position x1 to a second longitudinal position x3. And the assembly further includes a plurality of second type (different from the first type) aerodynamic add-ons 240, which are arranged on the suction side 26, extending from the first longitudinal position x1 to the second longitudinal position x3.

[0120] Thus, in Figure 6B the example shows another kind of asymmetry that can lead to the optimization of the blade assembly considering multiple different aerodynamic add-ons 230, 240. In Figure 6B the example, two different types of add-ons can be provided at the same longitudinal positions along the pressure and suction sides, rather than providing the same type of add-ons at different longitudinal positions along the pressure and suction sides as in Figure 6A the example.

[0121] In Figure 6B the example, the second type of aerodynamic add-on 240 has the same working principle as the first type of aerodynamic add-on 230 and has dimensions different from those of the first type of aerodynamic add-on. In Figure 6BIn certain examples, micro-vortex generators are provided on the suction side 26, while vortex generators are provided on the pressure side. The micro-vortex generators can be regarded here as smaller versions of the vortex generators. The micro-vortex generators are vortex generators that are smaller than the local boundary layer thickness.

[0122] In other examples, similar to the examples of Figure 6C the second type of aerodynamic add-on 240 has a working principle different from that of the first type of aerodynamic add-on 220. For example, the first type of aerodynamic add-on 220 can be an add-on (fins, ribs, or others) configured to reduce the noise of the wind turbine blade assembly in use. They are shown in this example as being arranged on the pressure side.

[0123] The second type of aerodynamic add-on 240 can be configured to increase lift or improve the aerodynamic efficiency of the wind turbine blade assembly in use (e.g., vortex generators, spoilers, or others). In this particular example, the vortex generator 240 can be arranged on the suction side.

[0124] In some examples, the wind turbine blade assembly may further include a plurality of third types (different from the first and second types) of aerodynamic add-ons. Specifically, in the example, the third type of add-ons can be provided along the outer half of the blade. The first and second types of add-ons can also be provided along the outer half of the blade.

[0125] In the illustrated example, the third type of aerodynamic add-on is a serration, specifically a triangular serration. It should be clear that depending on the specific design constraints and the specific objective function to be optimized, even additional types of aerodynamic add-ons can be used.

[0126] In still further examples, a plurality of aerodynamic add-ons can be arranged on the pressure side, extending from a first longitudinal position to a second longitudinal position, and a plurality of aerodynamic add-ons are arranged on the suction side, extending from a third longitudinal position to a fourth longitudinal position. The first, second, third, and fourth positions are arranged in the outer half of the wind turbine blade. The third longitudinal position does not coincide with the first longitudinal position, and / or the fourth longitudinal position does not coincide with the second longitudinal position.

[0127] That is, compared to the part of the blade where the aerodynamic add-ons are arranged on the suction side, the aerodynamic add-ons are arranged along different parts of the blade on the pressure side. The aerodynamic add-ons can be the same on the suction and pressure sides, or they can be different.

[0128] In a specific example, the first, second, third, and fourth positions are arranged in the outer third of the wind turbine blade. Specifically for the optimization of the blade's performance regarding noise, the outer third of the blade is important, and the optimization can lead to the use of multiple add-ons in the outer part of the blade.

[0129] In some examples, the aerodynamic add-on on the pressure side is a first type of aerodynamic add-on, and the aerodynamic add-on on the suction side is a second type of aerodynamic add-on different from the first type.

[0130] The second type of aerodynamic add-on may or may not have the same operating principle as the first type of aerodynamic add-on. The second type of aerodynamic add-on may or may not have a different size from the first type of aerodynamic add-on.

[0131] In Figure 6D shows yet another example of a wind turbine blade assembly according to the present disclosure. Figure 6D The example of shows a wind turbine blade assembly 100, including: a wind turbine blade 10 that extends longitudinally between a blade root 17 and a blade tip 15; and the wind turbine blade having a leading edge, a trailing edge, and a pressure side 24 and a suction side 26. The blade assembly 100 further includes: a plurality of aerodynamic add-ons 230 that are arranged on the pressure side 24 and extend from a first longitudinal position x1 to a second longitudinal position x2; and a plurality of aerodynamic add-ons 240 that are arranged on the suction side 26 and extend from the first longitudinal position x1 to the second longitudinal position x2. The blade assembly further includes a trailing edge serration 210 along the trailing edge from the first longitudinal position x1 to the second longitudinal position x2.

[0132] The blade assembly further includes: a plurality of aerodynamic add-ons 240 that are arranged on the pressure side between a third longitudinal position x3 and a fourth longitudinal position x4; and a plurality of aerodynamic add-ons 240 that are arranged on the suction side 26 between the third longitudinal position x3 and the fourth longitudinal position x4, wherein no trailing edge serration is provided between the third and fourth longitudinal positions.

[0133] Thus, according to this aspect, there is provided a blade assembly in which aerodynamic add-ons (e.g., on both the pressure side and the suction side) are combined with a trailing edge serration along a portion of the blade, and aerodynamic add-ons (e.g., on the pressure side and the suction side) along a portion of the blade where no trailing edge serration is provided.

[0134] These portions of the blade may be located in the outer half of the blade and, in some examples, in the outer third of the blade. In an example, the trailing edge serrations may be triangular serrations. In other examples, they may be, for example, conical serrations.

[0135] In this example, the add-ons 240 represent vortex generators, which may be provided on both the suction side 26 and the pressure side 24. The add-ons 230 represent micro-vortex generators, which may also be provided on both the suction side 26 and the pressure side 24. In other examples, the aerodynamic add-ons may be specifically configured to reduce noise and may be, for example.

[0136] In an example, on the suction side, the arrangement of the first plurality of aerodynamic add-ons is different from the arrangement of the second plurality of aerodynamic add-ons. Similarly, the arrangement of the third plurality of aerodynamic add-ons may be different from the arrangement of the fourth plurality of aerodynamic add-ons.

[0137] Figure 6D An example of a wind turbine blade assembly 100 according to still further aspects of the present disclosure is also illustrated, namely the assembly 100, including trailing edge serrations 210 extending from a first longitudinal position x1 to a second longitudinal position x2, and including no trailing edge serrations between the second longitudinal position x2 and a third longitudinal position x3, and further including trailing edge serrations 210 extending from the third longitudinal position x3 to a fourth longitudinal position x4.

[0138] The trailing edge serrations 210 are shown as triangular serrations, but they may also be other types of serrations, for example, conical serrations.

[0139] The various aspects illustrated herein may also be combined, i.e., the discontinuity of the trailing edge serrations as shown in Figure 6D may be combined with the additional asymmetries disclosed herein.

[0140] As shown in the previous example, the first and / or second aerodynamic add-ons may be one or more of the following: triangular trailing edge serrations, trailing edge conical serrations, fins, vortex generators, flaps, spoilers, and microtabs.

[0141] For completeness, some aspects of the present disclosure are set forth in the following numbered clauses: Clause 1. A wind turbine blade assembly, comprising: A wind turbine blade extending in a longitudinal direction between a blade root and a blade tip, and the wind turbine blade having a leading edge, a trailing edge, and a pressure side and a suction side, A plurality of aerodynamic add-ons of a first type arranged on the pressure side, extending from a first longitudinal position to a second longitudinal position, and A plurality of aerodynamic add-ons of a first type, which are arranged on the suction side and extend from a third longitudinal position to a fourth longitudinal position, and wherein the third longitudinal position does not coincide with the first longitudinal position, and / or the fourth longitudinal position does not coincide with the second longitudinal position. Clause 2. The wind turbine blade assembly according to Clause 1, wherein the third longitudinal position is closer to the blade tip than the second longitudinal position. Clause 3. The wind turbine blade assembly according to Clause 1 or 2, further comprising a plurality of aerodynamic add-ons of a second type. Clause 4. The wind turbine blade assembly according to Clause 3, wherein the aerodynamic add-ons of the second type are arranged between the first and second longitudinal positions and / or between the third and fourth longitudinal positions. Clause 5. The wind turbine blade assembly according to Clause 3 or 4, further comprising a plurality of aerodynamic add-ons of a third type. Clause 6. The wind turbine blade according to any one of Clauses 1-5, wherein the first and / or second aerodynamic add-ons are one or more of the following: triangular trailing edge serrations, trailing edge tapered serrations, fins, vortex generators, flaps, spoilers, and microtabs. Clause 7. The wind turbine blade assembly according to any one of Clauses 1-5, wherein the aerodynamic add-ons of the first type are add-ons configured to reduce the noise of the wind turbine blade assembly in use or add-ons configured to increase the lift of the wind turbine blade assembly in use. Clause 8. The wind turbine blade assembly according to any one of Clauses 1-7, wherein the first, second, third, and fourth longitudinal positions are arranged in the outer half of the wind turbine blade. Clause 9. The wind turbine blade assembly according to Clause 8, wherein the third and fourth longitudinal positions are arranged in the outer third of the wind turbine blade. Clause 10. A computer-implemented method for determining the configuration of a wind turbine blade assembly including a wind turbine blade and a plurality of aerodynamic add-ons, the method comprising: Receiving one or more design constraints; Receiving a wind speed distribution; Determining a virtual model for the basic design of the wind turbine blade; Determining a plurality of blade segments, wherein the blade segments correspond to portions of the wind turbine blade extending in the spanwise direction; and further comprising: a) Selecting one or more of the blade segments for modification; b) Generating an updated virtual blade assembly by changing the configuration of virtual aerodynamic add-ons in one or more of the selected blade segments, wherein the virtual aerodynamic add-ons are selected from a virtual library; c) Determining the performance of the updated virtual blade assembly based on the wind speed distribution by calculating an objective function; and Optimizing the objective function by repeating steps a)-c) until a convergence criterion has been met, while adhering to design constraints. Clause 11. The method according to Clause 10, wherein the objective function includes the performance of the blade with respect to noise. Clause 12. The method according to Clause 10 or 11, wherein the objective function includes the power output of the wind turbine. Clause 13. The method according to any of Clauses 10-12, wherein step b) includes selecting at least two different types of virtual aerodynamic add-ons from the library. Clause 14. The method according to any of Clauses 10-13, wherein step b) includes changing the position of the aerodynamic add-ons within one or more of the corresponding blade segments. Clause 15. The method according to any of Clauses 10-14, wherein step b) includes adding virtual aerodynamic add-ons to one or more of the selected blade segments. Clause 16. The method according to any of Clauses 10-15, wherein step b) includes migrating the virtual aerodynamic add-ons to one or more of the selected blade segments. Clause 17. The method according to any of Clauses 10-16, wherein optimizing the objective function includes using a genetic algorithm in a first set of iterations. Clause 18. The method according to Clause 17, wherein optimizing the objective function includes using a gradient-based algorithm in a second set of iterations after the first set of iterations. Clause 19. The method according to any of Clauses 10-18, wherein the design constraints include the maximum load on the wind turbine blade assembly. Clause 20. The method according to any of Clauses 10-19, wherein step c) includes determining the performance of the virtual blade assembly by calculating the performance of multiple blade segments. Clause 21. The method according to Clause 20, wherein calculating the performance of multiple blade segments includes using one or more engineering models to calculate the performance. Clause 22. A method according to any one of Clauses 10 - 21, and further comprising providing one or more of the following: a noise curve of a wind turbine blade assembly as a function of wind speed, a power curve of a wind turbine as a function of wind speed, one or more loads on a wind turbine blade assembly as a function of wind speed. Clause 23. A method according to any one of Clauses 10 - 22, and further comprising providing a layout of aerodynamic add-ons when a convergence criterion has been met. Clause 24. A method according to Clause 23, and further comprising manufacturing a wind turbine blade assembly according to a base design of a wind turbine blade and the provided layout of aerodynamic add-ons. Clause 25. A wind turbine blade obtainable by a method according to Clause 24. Clause 26. A computer program comprising instructions which, when the program is executed by a computer, cause the computer to perform a method according to any one of Clauses 10 - 23. Clause 27. A computer-readable data carrier on which the computer program of Clause 26 has been stored. Clause 28. A data carrier signal carrying the computer program of Claim 27. Clause 29. A data processing system configured to perform any one of the methods of Clauses 10 - 22. Clause 30. A data processing system comprising: A function for receiving one or more design constraints; A function for receiving a wind speed distribution; A function for determining a virtual model for a base design of a wind turbine blade; A function for determining a plurality of blade segments, where the blade segments correspond to portions of a wind turbine blade extending in the spanwise direction; and further comprising: A function for a) Selecting one or more of the blade segments for modification; b) Generating an updated virtual blade assembly by changing the configuration of virtual aerodynamic add-ons in one or more of the selected blade segments, where the virtual aerodynamic add-ons are selected from a virtual library; c) Determining the performance of the updated virtual blade assembly according to the wind speed distribution by calculating an objective function; and for optimizing the objective function by repeating steps a) - c) until a convergence criterion has been met, while complying with the design constraints. Clause 31. A wind turbine blade assembly comprising: A wind turbine blade that extends longitudinally between a blade root and a blade tip; and the wind turbine blade has a leading edge, a trailing edge, and a pressure side and a suction side, A plurality of aerodynamic add-ons of a first type, which are arranged on the pressure side and extend from a first longitudinal position to a second longitudinal position, and A plurality of aerodynamic add-ons of a second type, different from the first type, which are arranged on the suction side and extend from a first longitudinal position to a second longitudinal position. Clause 32. The wind turbine blade assembly as in Clause 31, wherein the aerodynamic add-ons of the second type have the same operating principle as the aerodynamic add-ons of the first type and have dimensions different from those of the aerodynamic add-ons of the first type. Clause 33. The wind turbine blade assembly as in Clause 31, wherein the aerodynamic add-ons of the second type have an operating principle different from that of the aerodynamic add-ons of the first type. Clause 34. The wind turbine blade assembly according to any one of Clauses 30-33, wherein the aerodynamic add-ons of the first type are add-ons configured to reduce the noise of the wind turbine blade assembly in use or add-ons configured to increase the lift of the wind turbine blade assembly in use. Clause 35. The wind turbine blade according to any one of Clauses 30-34, wherein the first and / or second aerodynamic add-ons are one or more of the following: triangular trailing edge serrations, trailing edge tapered serrations, fins, vortex generators, flaps, spoilers, and microtabs. Clause 36. The wind turbine blade assembly according to any one of Clauses 31-35, further comprising a plurality of aerodynamic add-ons of a third type. Clause 37. A wind turbine blade assembly comprising: A wind turbine blade that extends longitudinally between a blade root and a blade tip; and the wind turbine blade has a leading edge, a trailing edge, and a pressure side and a suction side, A plurality of aerodynamic add-ons, which are arranged on the pressure side and extend from a first longitudinal position to a second longitudinal position, and A plurality of aerodynamic add-ons, which are arranged on the suction side and extend from a third longitudinal position to a fourth longitudinal position, and wherein The first, second, third, and fourth positions are arranged in the outer half of the wind turbine blade, and wherein The third longitudinal position does not coincide with the first longitudinal position, and / or the fourth longitudinal position does not coincide with the second longitudinal position. Clause 38. A wind turbine blade assembly according to Clause 37, wherein the first, second, third, and fourth positions are arranged in the outer third of the wind turbine blade. Clause 39. A wind turbine blade assembly according to Clause 37 or 38, wherein the aerodynamic add-on on the pressure side is an aerodynamic add-on of a first type, and the aerodynamic add-on on the suction side is an aerodynamic add-on of a second type different from the first type. Clause 40. A wind turbine blade assembly as in Clause 39, wherein the aerodynamic add-on of the second type has the same working principle as the aerodynamic add-on of the first type and has dimensions different from those of the aerodynamic add-on of the first type. Clause 41. A wind turbine blade assembly as in Clause 39, wherein the aerodynamic add-on of the second type has a working principle different from that of the aerodynamic add-on of the first type. Clause 42. A wind turbine blade assembly according to any one of Clauses 39 - 41, wherein the aerodynamic add-on of the first type is an add-on configured to reduce the noise of the wind turbine blade assembly in use or an add-on configured to increase the lift of the wind turbine blade assembly in use. Clause 43. A wind turbine blade according to any one of Clauses 39 - 42, wherein the first and / or second aerodynamic add-ons are one or more of the following: triangular trailing edge serrations, trailing edge tapered serrations, fins, vortex generators, flaps, spoilers, and microtabs. Clause 44. A wind turbine blade assembly comprising a wind turbine blade that extends longitudinally between a blade root and a blade tip, and the wind turbine blade has a leading edge, a trailing edge, and a pressure side and a suction side, and further comprises trailing edge serrations along the trailing edge from a first longitudinal position to a second longitudinal position, and further comprises a first plurality of aerodynamic add-ons arranged on the pressure side, between the first and second longitudinal positions, and a second plurality of aerodynamic add-ons arranged on the suction side, between the first and second longitudinal positions, wherein the arrangement of the first plurality of aerodynamic add-ons is different from the arrangement of the second plurality of aerodynamic add-ons on the suction side. Clause 45. A wind turbine blade assembly according to Clause 44, wherein the second longitudinal position is at or near the tip of the blade. Clause 46. A wind turbine blade assembly according to Clause 44 or Clause 45, wherein the first longitudinal position is in the outer half of the blade, optionally within the outer third of the blade. Clause 47. A wind turbine blade assembly according to any one of Clauses 44 - 46, wherein the first plurality of aerodynamic appendages are different from the second plurality of aerodynamic appendages. Clause 48. A wind turbine blade assembly according to any one of Clauses 44 - 47, wherein the first plurality of aerodynamic appendages are arranged at a longitudinal position different from the longitudinal position at which the second plurality of aerodynamic appendages are located. Clause 49. A wind turbine blade assembly according to any one of Clauses 44 - 48, wherein the first plurality of aerodynamic appendages and / or the second plurality of aerodynamic appendages include appendages configured to reduce noise of the wind turbine blade assembly in use. Clause 50. A wind turbine blade assembly according to any one of Clauses 44 - 49, wherein the first plurality of aerodynamic appendages and / or the second plurality of aerodynamic appendages include appendages configured to increase lift of the wind turbine blade assembly in use. Clause 51. A wind turbine blade according to any one of Clauses 44 - 50, wherein the first plurality of aerodynamic appendages and / or the second plurality of aerodynamic appendages include one or more of the following: fins, vortex generators, flaps, spoilers, and microtabs. Clause 52. A wind turbine blade assembly according to any one of Clauses 44 - 51, wherein the first plurality of aerodynamic appendages on the pressure side have a different operating principle from the second plurality of aerodynamic appendages.

[0142] Clause 53. A wind turbine blade assembly comprising a wind turbine blade that extends in a longitudinal direction between a blade root and a blade tip and that has a leading edge, a trailing edge, and a pressure side and a suction side, further comprising a first plurality of aerodynamic appendages arranged on the pressure side, extending from a first longitudinal position to a second longitudinal position, and a second plurality of aerodynamic appendages arranged on the suction side, extending from a first longitudinal position to a second longitudinal position, and trailing edge serrations along the trailing edge from the first longitudinal position to the second longitudinal position, and the wind turbine blade assembly further comprising a third plurality of aerodynamic appendages arranged on the pressure side, between a third longitudinal position and a fourth longitudinal position, and a fourth plurality of aerodynamic appendages arranged on the suction side, between the third longitudinal position and the fourth longitudinal position, wherein no trailing edge serrations are provided between the third and fourth longitudinal positions. Clause 54. A wind turbine blade according to Clause 53, wherein the first and / or second and / or third and / or fourth plurality of aerodynamic appendages are one or more of the following: fins, vortex generators, flaps, spoilers, and microtabs. Clause 55. A wind turbine blade assembly according to Clause 53 or Clause 54, wherein the first to fourth longitudinal positions are in the outer half of the blade, optionally within the outer third of the blade. Clause 56. A wind turbine blade assembly according to any one of Clauses 53 - 55, wherein the first plurality of aerodynamic add-ons are different from the second plurality of aerodynamic add-ons. Clause 57. A wind turbine blade assembly according to any one of Clauses 53 - 56, wherein the third plurality of aerodynamic add-ons are different from the fourth plurality of aerodynamic add-ons. Clause 58. A wind turbine blade assembly according to any one of Clauses 53 - 57, wherein the first plurality of aerodynamic add-ons and / or the second plurality of aerodynamic add-ons include add-ons configured to reduce the noise of the wind turbine blade assembly in use. Clause 59. A wind turbine blade assembly according to any one of Clauses 53 - 58, wherein the third plurality of aerodynamic add-ons and / or the fourth plurality of aerodynamic add-ons include add-ons configured to reduce the noise of the wind turbine blade assembly in use. Clause 60. A wind turbine blade assembly according to any one of Clauses 53 - 59, wherein the first plurality of aerodynamic add-ons and / or the second plurality of aerodynamic add-ons include add-ons configured to increase the lift of the wind turbine blade assembly in use. Clause 61. A wind turbine blade assembly comprising a wind turbine blade that extends longitudinally between a blade root and a blade tip, and the wind turbine blade has a leading edge, a trailing edge, and a pressure side and a suction side, further comprising trailing edge serrations extending from a first longitudinal position to a second longitudinal position, and including no trailing edge serrations between the second longitudinal position and the third longitudinal position, and further comprising trailing edge serrations extending from the third longitudinal position to the fourth longitudinal position. Clause 62. The wind turbine blade assembly according to Clause 61, wherein the fourth longitudinal position is at or near the blade tip. Clause 63. The wind turbine blade assembly according to Clause 61 or 62, wherein the first, second, third, and fourth longitudinal positions are in the outer half of the blade, optionally within the outer third of the blade. Clause 64. The wind turbine blade assembly according to any one of Clauses 61 - 63, further comprising a first plurality of aerodynamic add-ons arranged on the suction side and / or on the pressure side, extending from the first longitudinal position to the second longitudinal position. Clause 65. A wind turbine blade assembly according to any of clauses 61 - 64 further comprises a second plurality of aerodynamic add-ons arranged on the pressure side and / or on the suction side, between a second and a third longitudinal position. Clause 66. A wind turbine blade assembly according to any of clauses 61 - 65, wherein the first plurality of aerodynamic add-ons is different from the second plurality of aerodynamic add-ons. Clause 67. A wind turbine blade assembly according to any of clauses 61 - 66, wherein the first plurality of aerodynamic add-ons and / or the second plurality of aerodynamic add-ons comprises add-ons configured to reduce the noise of the wind turbine blade assembly in use. Clause 68. A wind turbine blade assembly according to any of clauses 61 - 67, wherein the first plurality of aerodynamic add-ons and / or the second plurality of aerodynamic add-ons comprises add-ons configured to increase the lift of the wind turbine blade assembly in use. Clause 69. A wind turbine blade according to any of clauses 61 - 68, wherein the first and / or second plurality of aerodynamic add-ons is one or more of the following: fins, vortex generators, flaps, spoilers, and microtabs. Clause 70. A wind turbine blade assembly according to any of clauses 61 - 69, wherein the trailing edge serrations are triangular serrations or conical serrations.

[0143] This written description uses examples to disclose the teachings, including the preferred embodiments, and also enables any person skilled in the art to practice the teachings, including making and using any device or system and performing any incorporated method. The scope of patentable subject matter is defined by the claims and may include other examples that occur to those skilled in the art. If such other examples have structural elements that are not different from the literal language of the claims, or if they include equivalent structural elements that have non-substantive differences from the literal language of the claims, then such other examples are intended to be within the scope of the claims. Aspects from the various described embodiments and other known equivalents for each such aspect can be mixed and matched by those of ordinary skill in the art to construct additional embodiments and techniques in accordance with the principles of this application. If reference numerals associated with the figures are placed in parentheses in the claims, they are merely for attempting to increase the understandability of the claims and should not be construed as limiting the scope of the claims.

Claims

1. A computer-implemented method for determining a configuration of a wind turbine blade assembly including a wind turbine blade and a plurality of aerodynamic add-ons, the method comprising: Receiving one or more design constraints; Receiving a wind speed distribution; Determining a virtual model for a baseline design of the wind turbine blade; Determining a plurality of blade segments, wherein the blade segments correspond to portions of the wind turbine blade extending in the spanwise direction; and further comprising: a) Selecting one or more of the blade segments for modification; b) Generating an updated virtual blade assembly by changing the configuration of virtual aerodynamic add-ons in one or more of the selected blade segments, wherein the virtual aerodynamic add-ons are selected from a virtual library; c) Determining the performance of the updated virtual blade assembly based on the wind speed distribution by computing an objective function; and Optimizing the objective function by repeating steps a)-c) until a convergence criterion has been met, while adhering to the design constraints.

2. The method according to claim 1, wherein, The objective function includes the performance of the wind turbine blade assembly with respect to noise.

3. The method according to claim 1 or 2, wherein The objective function includes the power output of the wind turbine.

4. The method according to any one of claims 1 - 3, wherein, Step b) includes selecting at least two different types of virtual aerodynamic add-ons from the library.

5. The method according to any one of claims 1 - 4, wherein, Step b) includes changing the position of the aerodynamic add-ons within one or more of the corresponding blade segments.

6. The method according to any one of claims 1-5, wherein Step b) includes adding virtual aerodynamic add-ons to one or more of the selected blade segments.

7. The method according to any one of claims 1-6, wherein, Step b) includes migrating virtual aerodynamic add-ons to one or more of the selected blade segments.

8. The method according to any one of claims 1-7, wherein, Optimizing the objective function includes using a genetic algorithm in a first set of iterations.

9. The method according to claim 8, wherein Optimizing the objective function includes using a gradient-based algorithm in a second set of iterations after the first set of iterations.

10. The method according to any one of claims 1-9, wherein, Step c) includes determining the performance of the updated virtual blade assembly by computing the performance of the plurality of blade segments.

11. The method according to claim 10, wherein, Computing the performance of the plurality of blade segments includes using one or more engineering models to compute the performance.

12. The method according to any one of claims 1-11, and further comprising: Providing a layout of the aerodynamic add-ons when the convergence criterion has been met, and further comprising: manufacturing the wind turbine blade assembly based on the baseline design of the wind turbine blade and the provided layout of the aerodynamic add-ons.

13. A wind turbine blade obtainable by the method according to claim 12.

14. A computer program comprising instructions which, when the program is executed by a computer, cause the computer to perform the method according to any one of claims 1-12.

15. A data processing system comprising: A function for receiving one or more design constraints; A function for receiving a wind speed distribution; A function for determining a virtual model for a baseline design of a wind turbine blade; A function for determining a plurality of blade segments, wherein the blade segments correspond to portions of the wind turbine blade extending in the spanwise direction; and further comprising: A function for the following operations a) Selecting one or more of the blade segments for modification; b) generating an updated virtual blade assembly by changing the configuration of the virtual aerodynamic add-ons in one or more of the selected blade segments, wherein the virtual aerodynamic add-ons are selected from a virtual library; c) determining the performance of the updated virtual blade assembly according to the wind speed distribution by calculating an objective function; and optimizing the objective function by repeating steps a)-c) until a convergence criterion has been met, while complying with design constraints.

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