Noise reduction structure for flap side edge

Abstract

The present application relates to the field of aeronautical engineering and air dynamic noise control, and provides a noise reduction structure for a flap side edge. The noise reduction structure for the flap side edge comprises a three-dimensional gradually-changing leading edge flow guide structure arranged at the front end entrance of the flap side edge; a side edge vortex resistance baffle plate in a sheet-like structure arranged downstream of the three-dimensional gradually-changing leading edge flow guide structure; and a sawtooth-shaped upper edge vortex control structure arranged at the upper edge of the side edge vortex resistance baffle plate away from the flap surface. The noise reduction structure for the flap side edge can reduce the velocity difference with the root low-energy shear layer, destroy the formation condition of the primary large vortex, solve the core source of the wideband noise, avoid high-frequency noise peaks, and greatly reduce the wideband noise intensity.

Description

Technical Field

[0001] This invention relates to the field of aeronautical engineering and aerodynamic noise control, and provides a noise reduction structure for the side edge of a flap. Background Technology

[0002] With the development of the aviation industry, noise pollution has become an increasing concern for aviation companies and communities. This noise mainly occurs during the takeoff and landing phases of an aircraft, especially when the aircraft flaps are deployed.

[0003] Flaps are part of an aircraft wing, pulled down during takeoff and landing to increase lift. However, when flaps are deployed, their side edges are prone to forming what is known as "shear layer separation," a phenomenon where the high-speed airflow of the aircraft is entrained by a low-energy shear layer. This phenomenon not only generates loud noise but can also cause problems such as unstable contrails.

[0004] Currently, several noise reduction technologies have been proposed both domestically and internationally to address this issue.

[0005] For example, rounded structures cannot fundamentally suppress large-scale edge vortices. Existing large rounded edge structures mainly rely on geometric smoothing to delay separation, but they cannot fundamentally change the basic mechanism of mutual entrainment between high-energy incoming flow and low-energy shear layer at the flap edge. Therefore, large-scale "edge master vortex" still forms; the vortex structure exists stably, is large in scale, and has high energy; and it cannot eliminate the main vortex source that causes broadband noise.

[0006] The improvement in mid-to-high frequency noise is limited. The mid-to-high frequency noise at the flap side edge mainly originates from high-speed small-scale disturbances in the shear layer and unsteady energy exchange generated by the interaction between large and small eddies. Traditional rounded or simple guiding structures cannot effectively disperse small-scale eddy structures. Therefore, the improvement in high-frequency noise is minimal; significant noise spikes still form at ground observation points.

[0007] Due to their complex structure, high weight, and limited engineering implementation, some existing structures (such as complex winglets, multiple guide vanes, and multi-layer porous materials) have the following characteristics: a large number of parts, complex processing, high weight, and are not convenient for modular installation or maintenance. This limits their application in civil airliner flaps, light drones, and small aircraft.

[0008] The noise reduction is limited and cannot meet the requirements of the next generation of induced draft noise control. Existing technologies can usually only achieve an overall noise reduction of 1 to 2 dBA; high-frequency noise is not significantly improved; large-scale vortices still exist and the wake is unstable.

[0009] However, this level is no longer sufficient for modern civilian and military platforms that require lower noise and higher stealth.

[0010] Furthermore, although existing technologies such as CN116424544A employ superior smooth side edges and certain flow guiding concepts, their structures are essentially still modifications of the traditional inverted round type. Consequently, problems such as the continued presence of large-scale vortices on the side edges, limited improvement in high-frequency noise, and failure to fundamentally change the development mode of the shear layer persist.

[0011] In summary, while these methods can partially reduce noise, they still have many problems, such as the inverted rounded structure being unable to suppress large-scale side edge vortices at the source, the limited improvement in mid-to-high frequency noise, the complex structure, the high weight, the limitations in engineering implementation, and the limited noise reduction that cannot meet the requirements for aerodynamic noise control. Summary of the Invention

[0012] This invention provides a noise reduction structure for the side edge of a flap, which addresses the shortcomings of related technologies, such as the difficulty in eliminating large-scale vortices, insufficient control of high-frequency noise, difficulty in implementation when the structural size is limited, and insufficient noise reduction amplitude.

[0013] This invention provides a noise reduction structure for the side edge of a flap, comprising: A three-dimensional gradient leading edge guide structure is set at the front inlet of the flap side edge; Side edge vortex-blocking baffle, which is a thin sheet structure, is disposed downstream of the three-dimensional gradient leading edge guide structure; A sawtooth-shaped upper edge vortex control structure is disposed on the upper edge of the side edge vortex blocking baffle away from the flap surface.

[0014] According to one embodiment of the present invention, the outer surface, sweep angle and lateral outward bulge of the three-dimensional gradient leading edge guide structure are all continuously and smoothly varied along the span of the flap.

[0015] According to one embodiment of the present invention, the height of the side-edge vortex-damping baffle is 1 to 3 times the local thickness of the flap side-edge.

[0016] According to one embodiment of the present invention, the thickness of the side edge vortex-blocking baffle is 1 to 3 millimeters.

[0017] According to one embodiment of the present invention, the leading edge of the side edge vortex baffle is smoothly connected to the trailing edge of the three-dimensional gradient leading edge guide structure by means of an arc, spline curve or smooth curve.

[0018] According to one embodiment of the present invention, the sawtooth upper edge vortex control structure includes a plurality of sawtooths continuously distributed along the upper edge of the side edge vortex blocking baffle; The ratio of the height of the saw teeth to the wavelength is 2 to 3.

[0019] According to one embodiment of the invention, the ratio of the wavelength of the sawtooth to the boundary layer thickness at the flap side edge is 1.2 to 2.

[0020] According to one embodiment of the present invention, the shape of the saw teeth is an isosceles triangle, trapezoid, sector, staggered shape, or a composite shape composed of at least two of the aforementioned shapes.

[0021] According to one embodiment of the present invention, the three-dimensional gradient leading edge guide structure, the side edge vortex baffle and the sawtooth upper edge vortex control structure are connected by surfaces with continuous curvature to form an integrated shape.

[0022] According to one embodiment of the present invention, the trailing edge of the side edge vortex deflector is formed as a straight line, a broken line with an upward inflection angle, or a curve with a predetermined curvature change.

[0023] According to embodiments of the present invention, the noise reduction structure for the flap side edge, a three-dimensional gradient leading-edge guiding structure, through spanwise gradient design, guides the high-energy incoming flow to actively deflect outward, reducing the velocity difference with the low-energy shear layer at the root and disrupting the formation conditions of the initial large eddy. Side-edge vortex-blocking baffles physically block the entrainment path of the shear layer, preventing small-scale vortices from merging into large-scale vortices, thus completely eliminating the side-edge main vortex that traditional rounded structures cannot eliminate. The two structures work together to address the core source of broadband noise from a flow mechanism perspective, significantly reducing broadband noise intensity. The multi-scale disturbances generated by the sawtooth upper-edge vortex-controlling structure disrupt the coherence of the high-frequency vortex structure, causing the tightly stacked small-scale vortex filaments to break and disperse, reducing energy concentration in the high-frequency band. This structure specifically addresses the limited improvement in high-frequency noise in traditional solutions, making the noise spectrum smoother and avoiding high-frequency noise spikes, with particularly outstanding noise reduction effects in key high-frequency ranges. The synergistic effect of the three-segment structure results in a uniform and stable three-dimensional weak vortex structure in the wake, eliminating the contribution of unsteady noise caused by wake instability. Side-edge vortex deflectors smooth the wake region, reducing interference between the jet stream and the wing body. Three-dimensional gradient guides and sawtooth vortex control further optimize the wake morphology, preventing airflow separation and turbulence generation, with no new sources of additional noise. The overall structure has no complex mechanical parts; the three-dimensional gradient leading-edge guide structure, side-edge vortex deflectors, and sawtooth upper-edge vortex control structure are all made of lightweight materials, resulting in extremely light weight and no increase in the overall load of the flaps. The structure is compact with a short span, having minimal impact on wingspan, and can be directly integrated into various existing flaps, adaptable to various aircraft such as civil airliners and drones. It boasts strong engineering manufacturability and can be realized through composite material layup, 3D printing, and other processes. The design of each structure is adapted to the original aerodynamic shape of the flaps, without significantly altering the flaps' core aerodynamic parameters such as lift and drag. The three-dimensional gradient flow guide structure is smoothly connected to the flaps. The thin-plate design of the side edge vortex deflector reduces airflow loss. The serrated upper edge vortex control structure has moderate disturbance intensity, ensuring noise reduction without affecting the flight performance of the flaps. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0025] Figure 1 This is a schematic perspective view of one angle of the noise reduction structure of the flap side edge provided by the present invention.

[0026] Figure 2 This is a schematic perspective view of the noise reduction structure of the flap side edge provided by the present invention from another angle.

[0027] Figure 3 This is a schematic top view of the noise reduction structure of the flap side edge provided by the present invention.

[0028] Figure 4 This is a schematic partial enlarged view of the noise reduction structure of the sawtooth upper edge vortex control structure provided by the present invention.

[0029] Figure 5 This is a flow field vorticity diagram of the initial structure of the flap side edge.

[0030] Figure 6 This is a flow field vorticity diagram of the noise reduction structure of the flap side edge provided by the present invention.

[0031] Figure 7 This is a flow field vorticity diagram showing the breakage of the vortex wire at the sawtooth position in the noise reduction structure of the flap side edge provided by the present invention.

[0032] Figure 8 This is a comparison chart of the A-weighted curve spectrum of the sound pressure level at the position directly below the flap provided by the present invention.

[0033] Figure label: 100. Three-dimensional gradient leading edge guide structure; 102. Side edge vortex-blocking baffle; 104. Sawtooth upper edge vortex-controlling structure. Detailed Implementation

[0034] The embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. The following examples are for illustrative purposes only and should not be construed as limiting the scope of the invention.

[0035] like Figures 1 to 8 As shown, an embodiment of the present invention provides a noise reduction structure for the side edge of a flap, comprising: A three-dimensional gradient leading edge guide structure 100 is set at the front inlet of the flap side edge; Side edge vortex-blocking baffle 102, which is a thin sheet structure, is located downstream of the three-dimensional gradient leading edge guide structure 100. The sawtooth-shaped upper edge vortex control structure 104 is located on the upper edge of the side edge vortex blocking baffle 102 away from the flap surface.

[0036] According to the noise reduction structure for the flap side edge provided in this embodiment of the invention, the three-dimensional gradient leading edge guiding structure 100 guides the high-energy incoming flow to actively deflect outward through spanwise gradient design, reducing the velocity difference with the low-energy shear layer at the root and disrupting the formation conditions of the initial large eddy. The side edge vortex-blocking baffle 102 physically blocks the entrainment path of the shear layer, preventing small-scale vortices from merging into large-scale vortices, thus completely eliminating the side edge main vortex that cannot be eliminated by traditional rounded structures. The two work together to solve the core source of broadband noise from the flow mechanism, significantly reducing the broadband noise intensity. The multi-scale disturbance generated by the sawtooth upper edge vortex control structure 104 disrupts the coherence of the high-frequency vortex structure, causing the tightly stacked small-scale vortex filaments to break and disperse, reducing the energy concentration phenomenon in the high-frequency band. This structure specifically solves the problem of limited high-frequency noise improvement in traditional solutions, making the noise spectrum smoother and avoiding high-frequency noise spikes, especially with outstanding noise reduction effect in the key high-frequency range. The synergistic effect of the three-segment structure makes the wake present a uniform and stable three-dimensional weak vortex structure, eliminating the unsteady noise contribution caused by wake instability. The side-edge vortex deflector 102 smooths the wake region, reducing interference between the jet stream and the wing body. The three-dimensional gradient guide and sawtooth vortex control further optimize the wake morphology, preventing airflow separation and turbulence generation, with no new additional noise sources. The overall structure has no complex mechanical parts. The three-dimensional gradient leading-edge guide structure 100, the side-edge vortex deflector 102, and the sawtooth upper-edge vortex control structure 104 are all made of lightweight materials, resulting in extremely light weight and no increase in the overall load of the flap. The structure is compact with a short span, having minimal impact on wingspan. It can be directly integrated into various existing flaps, adapting to various aircraft such as civil airliners and UAVs. It has strong engineering manufacturability and can be realized through composite material layup, 3D printing, and other processes. The design of each structure is adapted to the original aerodynamic shape of the flap, without significantly altering the flap's core aerodynamic parameters such as lift and drag. The three-dimensional gradient flow guide structure is smoothly connected to the flaps. The thin-plate design of the side edge vortex deflector 102 reduces airflow loss. The serrated upper edge vortex control structure 104 has moderate disturbance intensity, ensuring noise reduction without affecting the flight performance of the flaps.

[0037] Please continue reading Figures 1 to 8 The noise reduction structure for the flap side edge provided in this embodiment of the invention suppresses noise sources from the root through a three-stage design of three-dimensional gradient flow guide, vortex baffle, and sawtooth vortex control.

[0038] Specifically, the three-dimensional gradient leading-edge guide structure 100 is fixedly installed at the front inlet of the flap side edge, smoothly connecting with the aerodynamic shape of the flap side edge. Its curved surface changes continuously and smoothly along the flap spanwise, without steps or abrupt changes; the curvature gradually transitions from one end to the other, forming a natural and smooth guide profile. The sweep angle adjusts synchronously along the spanwise, coordinating with the gradual change in curved surface to ensure that the airflow injection angle is adapted to different spanwise positions. The lateral outward bulge continuously changes along the spanwise, guiding the high-energy incoming flow to deflect outward, weakening the velocity difference of the shear layer, and reshaping the velocity field from the inlet. This structure achieves vortex control through its three-dimensional surface itself, without additional complex components such as winglets, presenting an integrated guide shape.

[0039] The side-edge vortex-blocking baffle 102 is a thin-plate structure, fixedly installed downstream of the three-dimensional gradient leading-edge guide structure 100, maintaining a preset distance from the trailing edge of the guide structure. The baffle is perpendicular to the flap surface and arranged along the entire span of the flap, covering the entire side-edge shear layer development area. The baffle is made of high-strength, lightweight material with a smooth surface. Its leading-edge profile adapts to the airflow trajectory, while its trailing edge is a straight line or a gentle curve, reducing airflow around-flow losses. The baffle's installation position precisely corresponds to the critical path of shear layer entrainment, physically blocking the merging trend of small-scale flows without significantly increasing aerodynamic drag.

[0040] The sawtooth-shaped upper edge vortex control structure 104 is integrally formed on the upper edge of the side edge vortex deflector 102, away from the flap surface. It is continuously distributed along the upper edge of the deflector without gaps or breaks. The sawtooths are evenly arranged along the spanwise direction, and their shape is adapted to the dispersion requirements of high-frequency vortices, enabling the generation of multi-scale disturbances. The distribution of the sawtooths covers the entire upper edge of the deflector, ensuring that there are no dead angles in the disturbance of the airflow. It forms an integrated structure with the main body of the deflector, and the connection parts are smoothly transitioned without sharp protrusions to avoid generating additional noise.

[0041] A three-dimensional gradient leading-edge guide structure 100 guides the airflow outward, weakening the conditions for the formation of primary vortices; a side-edge vortex-blocking baffle 102 blocks the secondary entrainment path of the shear layer, suppressing the merging of large vortices; and a sawtooth-shaped upper-edge vortex-controlling structure 104 disperses high-frequency small-scale vortices. The three structures are arranged sequentially along the airflow direction to form a continuous vortex-controlling link. The aerodynamic profiles of each structure are mutually adapted, with no obvious aerodynamic interference, and together they constitute a full-link control system for flap side-edge noise, adapting to the airflow characteristics when the flaps are deployed.

[0042] According to one embodiment of the present invention, the outer surface, sweep angle and lateral outward bulge of the three-dimensional gradient leading edge guide structure 100 are all continuously and smoothly varied along the span of the flap.

[0043] In one embodiment of the present invention, the three-dimensional gradient leading edge guide structure 100 optimizes the airflow state from the source through a continuous and smooth change along the spanwise direction.

[0044] The three-dimensional gradient leading edge guide structure 100 has a continuously smooth curved surface along the flap span, without steps or abrupt changes. The curvature of the surface gradually transitions from one end to the other, forming a natural and smooth guide profile. This curved surface design adapts to the airflow inlet shape of the flap side edge, guiding the high-energy incoming flow along a preset trajectory and avoiding separation caused by abrupt changes in airflow.

[0045] The sweep angle is adjusted smoothly and synchronously along the span, coordinating with the gradual change in the shape surface to keep the airflow inlet angle at different spanwise positions appropriate, reducing local airflow impact. The trend of the sweep angle change matches the aerodynamic shape of the flap, ensuring that the airflow can flow smoothly through the guide structure throughout the entire spanwise range without generating local vortices.

[0046] The lateral bulge varies continuously along the span, gradually adjusting from the flap root to the tip, creating differentiated lateral flow guidance effects in the spanwise direction. The bulge near the root region adapts to the flow characteristics of the root airflow, while the bulge near the tip region guides the airflow outward, reducing the velocity difference of the shear layer.

[0047] The gradual changes in the curved surface, sweep angle, and lateral outward bulge work together to form a unified three-dimensional guiding shape. The consistent rhythm of these three elements ensures that the airflow can achieve a stable guiding effect at all positions in the spanwise direction, reshaping the velocity field from the inlet and laying the foundation for subsequent vortex control.

[0048] The continuously varying structure causes the high-energy incoming flow to naturally deflect outward, reducing the velocity difference with the low-energy shear layer at the root. This weakens the shear layer's entrainment force at its source, preventing the formation of large-scale side-edge main vortices and overcoming the shortcomings of traditional rounded structures in suppressing large-scale vortices. The varying design makes the spanwise velocity distribution more uniform, weakens the increase in shear layer thickness, makes the airflow more body-fitting and the streamlines smoother, reduces abrupt changes in the flow field, and creates favorable conditions for the subsequent work of the side-edge vortex-blocking baffle 102 and the sawtooth upper-edge vortex-controlling structure 104.

[0049] Furthermore, the smooth, gradually changing curved surface without abrupt changes avoids airflow separation on the surface of the guide structure, reducing additional noise caused by airflow separation, while improving the aerodynamic efficiency of the guide structure without adding extra flight drag. The continuous spanwise variation allows the guide structure to adapt to airflow characteristics at different spanwise positions, ensuring stable guidance throughout the entire flap side-edge inlet area and avoiding noise bounce caused by localized guide failure.

[0050] According to one embodiment of the present invention, the height of the side-edge vortex deflector 102 is 1 to 3 times the local thickness of the flap side-edge.

[0051] In one embodiment of the present invention, the side edge vortex-blocking baffle 102 is designed with a specific height to effectively block the shear layer entrainment path.

[0052] The height of the side-edge vortex deflector 102 is determined based on the local thickness of the flap side edge, ensuring that the height covers the main development area of ​​the shear layer. The height design satisfies the need to block entrainment without being too high, which would cause a significant increase in airflow drag, or too low, which would fail to prevent shear layer merging.

[0053] Along the spanwise direction of the flap, the height of the side-edge vortex-blocking baffle 102 maintains a proportion that matches the local airfoil thickness at the corresponding position, ensuring effective coverage of the shear layer throughout the entire spanwise range and preventing secondary entrainment due to insufficient local height. The baffle height works in conjunction with the gradient characteristics of the three-dimensional gradient leading-edge guide structure 100 to form a continuous vortex control link.

[0054] The baffle height ensures its insertion into critical locations in the shear layer development. When small-scale flows attempt to entrain and merge, the baffle provides a physical barrier, preventing the full formation of potential large vortices. The height design also provides a mounting base for the subsequent sawtooth upper-edge vortex control structure 104, ensuring that the sawtooth can act on key areas of the airflow.

[0055] While meeting the height design requirements, the baffle adopts a thin sheet structure. Through material selection (such as high-strength metals and composite materials), the structural strength is ensured to avoid deformation or damage caused by airflow impact and ensure stable vortex control effect during long-term use.

[0056] The height design, adapted to the local wing thickness, allows the baffle to effectively insert into the shear layer, blocking the entrainment path of the shear layer, preventing small-scale vortices from merging into large-scale vortices, and solving the problem that traditional structures cannot suppress secondary entrainment. The height of the baffle ensures that it can intervene in the development of the wake, making the wake region smoother, eliminating the main unsteady contributions in the noise source, avoiding noise enhancement caused by wake instability, and improving the aerodynamic stability of the wake.

[0057] The height design balances vortex control requirements with aerodynamic drag, effectively preventing entrainment without significantly increasing airflow resistance due to excessive baffle height. This ensures the aerodynamic efficiency of the guide structure and does not affect the overall aerodynamic performance of the flaps. The reasonable height provides an ideal installation position for the sawtooth upper edge vortex control structure 104, allowing the sawtooth to precisely act on the airflow after passing the baffle, achieving a synergistic superposition of vortex control effects and improving noise reduction performance across the entire frequency band.

[0058] According to one embodiment of the present invention, the thickness of the side edge vortex-blocking baffle 102 is 1 to 3 mm.

[0059] In one embodiment of the present invention, the side edge vortex deflector 102 adopts a thin sheet structure, and the structural performance and aerodynamic effect are balanced through precise thickness design.

[0060] The side-edge vortex-damping baffle 102 is designed to be thin-sheet, ensuring a lightweight structure while maintaining sufficient structural strength and rigidity. The thickness is chosen to suit the material properties; both metal and composite materials can achieve a balance between lightweight and strength through this thickness design.

[0061] The thickness of the baffle remains uniform along its height and span, without any local thickening or thinning, ensuring that the airflow experiences uniform force as it passes over the baffle surface and does not generate local airflow disturbances. The uniform thickness ensures smooth airflow over the baffle surface and avoids local eddies caused by uneven thickness.

[0062] The thin, sheet-like design allows the baffle to be easily installed downstream of the three-dimensional gradient leading edge guide structure 100 without taking up too much space, and the connection with the guide structure is more compact. The thickness design also adapts to the one-piece molding process, facilitating connection with other structures through surfaces with continuous curvature.

[0063] The thin, sheet-like structure reduces the area obstructing airflow, minimizing airflow losses and avoiding additional noise caused by excessively thick baffles. Simultaneously, sufficient thickness ensures the baffle can withstand airflow impacts without vibration or deformation, guaranteeing the stability of the vortex control effect.

[0064] The thin-film design significantly reduces the structural weight of the baffle. Compared with the traditional complex winglet structure, it has a significant weight advantage, solving the problem of the high weight and limited engineering application of traditional noise reduction structures. It is easy to apply to various aircraft such as civil airliners and light drones.

[0065] The thinner thickness reduces the contact area between the airflow and the baffle, lowers the airflow drag and separation loss, improves the aerodynamic efficiency of the entire noise reduction structure, and does not affect the lift performance of the flap.

[0066] The thin sheet structure allows the airflow to flow smoothly around the surface, without generating local airflow separation and turbulent noise caused by excessive thickness of the structure, ensuring that the baffle does not introduce new noise sources while blocking entrainment.

[0067] The uniform thickness design facilitates the use of various engineering manufacturing processes such as carbon fiber composite lay-up and 3D printing, reducing manufacturing costs and improving the engineering feasibility and mass production capability of the structure.

[0068] According to one embodiment of the present invention, the leading edge of the side edge vortex baffle 102 is smoothly connected to the trailing edge of the three-dimensional gradient leading edge guide structure 100 by means of an arc, spline curve or smooth curve.

[0069] In one embodiment of the present invention, the side edge vortex deflector 102 is designed with a smooth connection to ensure a smooth transition of airflow from the guide structure to the deflector.

[0070] The leading edge of the side-edge vortex-blocking baffle 102 is connected to the trailing edge of the three-dimensional gradually changing leading edge guide structure 100 by means of an arc, spline curve, or smooth curve. The curvature of the curve is continuous with the curvature of the trailing edge of the guide structure, forming a transition profile without abrupt changes. The design of the connecting curve is adapted to the trajectory of the airflow after it flows out of the guide structure, guiding the airflow smoothly into the baffle area.

[0071] The surface at the joint is smooth, without any protrusions or depressions. The surface of the guide structure and the baffle forms a continuous aerodynamic surface, preventing abrupt changes in airflow as it passes through the joint and avoiding airflow separation or the generation of local vortices. The machining precision of the joint surface is strictly controlled to ensure the smoothness of the curve and improve the airflow transition effect.

[0072] Along the spanwise direction of the flap, the connection method between the guide structure and the baffle is consistent, and the trend of the curve changes in coordination with the spanwise gradual change characteristics of both, ensuring that the airflow can achieve a smooth transition throughout the entire spanwise range, without airflow turbulence caused by poor local connection.

[0073] The smooth connection design works in conjunction with the vortex control function of both components. The airflow after the optimization of the guide structure smoothly enters the baffle area through the connection curve. The baffle can accurately act on the airflow that has undergone preliminary vortex control, further blocking the entrainment path and achieving continuous superposition of vortex control effects.

[0074] The smooth transition curve avoids the separation of airflow between the guide structure and the baffle, allowing the airflow to flow continuously through the two structures, reducing additional noise caused by sudden changes in airflow, and improving the aerodynamic coherence of the entire noise reduction structure.

[0075] The seamless transition allows the velocity field optimization effect of the guide structure to continue, and the baffle can further block entrainment on the basis of the optimized airflow. The two form a synergistic vortex control link, which improves the suppression effect on large-scale vortices.

[0076] The smooth surface at the joint avoids local airflow disturbance and turbulence, reduces the noise contribution of the joint area, and solves the problem of additional noise easily generated by the joint of multi-segment structures.

[0077] The smooth connection makes the guide structure and the baffle form an almost integrated aerodynamic shape, reducing aerodynamic interference between structures, while improving the mechanical coherence of the structure and enhancing the stability and durability of the overall structure.

[0078] According to one embodiment of the present invention, the sawtooth upper edge vortex control structure 104 includes a plurality of sawtooths continuously distributed along the upper edge of the side edge vortex blocking baffle 102; The ratio of the height of the sawtooth to the wavelength is 2 to 3.

[0079] In one embodiment of the present invention, the sawtooth upper edge vortex control structure 104 enhances high-frequency noise suppression through a sawtooth design with a specific ratio.

[0080] The sawtooth upper edge vortex control structure 104 includes multiple sawtooths continuously distributed along the upper edge of the side edge vortex blocking baffle 102. There are no gaps or breaks between the sawtooths, forming a complete sawtooth band, ensuring that the disturbance of the airflow covers the entire upper edge of the baffle.

[0081] The height of the sawtooth is kept in a specific ratio to the wavelength. This ratio is designed to produce the optimal disturbance effect, ensuring that the disturbance intensity is sufficient to break up small-scale vortices without causing excessive airflow drag due to an imbalance in the ratio. The height-to-wavelength ratio is adapted to the structural characteristics of high-frequency vortices, specifically disrupting their coherence.

[0082] All the saw teeth have a consistent height and wavelength ratio and are evenly distributed along the upper edge of the baffle. This ensures that the intensity of the disturbance to the airflow by the saw teeth is uniform throughout the span, avoiding insufficient or excessive disturbance in certain areas, so that the airflow can obtain stable multi-scale processing at all positions in the span.

[0083] The fixed sawtooth is firmly connected to the side-edge vortex-blocking baffle 102, with a smooth transition at the connection point and no sharp protrusions, avoiding airflow separation caused by the connection structure. The root of the sawtooth is fused with the upper edge of the baffle to form an integrated structure, ensuring structural strength without affecting airflow.

[0084] A specific ratio of sawtooths generates multi-scale perturbations at the trailing edge, causing small-scale vortices to no longer maintain consistent spatial coherence, effectively suppressing the main peak of high-frequency noise and solving the problem of limited improvement of mid-to-high-frequency noise by traditional structures.

[0085] The serrated perturbation makes the shear layer more uniform, and the wake exhibits a multi-scale weak vortex structure, reducing the energy concentration phenomenon in the high-frequency band, making the noise spectrum smoother, and avoiding the generation of high-frequency noise spikes.

[0086] The optimized ratio of height to wavelength allows the sawtooth to act precisely on the high-frequency vortex structure, breaking up the tightly stacked small-scale vortices, causing the vortex wires to break and disperse, significantly reducing high-frequency noise energy, especially in the critical high-frequency range where the noise reduction effect is outstanding.

[0087] The sawtooth-shaped upper edge vortex control structure 104 inherits the vortex control effect of the side edge vortex blocking baffle 102, further processing the airflow after passing through the baffle to form a full-link noise reduction that suppresses large-scale vortices, blocks secondary entrainment, and disperses high-frequency small vortices, covering a wide range of noise sources.

[0088] According to one embodiment of the invention, the ratio of the wavelength of the serrations to the boundary layer thickness at the flap side edge is 1.2 to 2.

[0089] In one embodiment of the present invention, the sawtooth upper edge vortex control structure 104 optimizes the disturbance effect by adapting the sawtooth wavelength to the boundary layer thickness.

[0090] The wavelength of the sawtooth is kept in a specific ratio to the boundary layer thickness at the side edge of the flap. The wavelength size is determined according to the boundary layer thickness to ensure that the sawtooth can penetrate deep into the boundary layer and directly disturb the small-scale eddies in the boundary layer. This avoids the wavelength being too large to act on the boundary layer or too small to cause excessive disturbance.

[0091] Along the spanwise direction of the flap, the boundary layer thickness varies. The wavelength of the sawtooth can be adaptively adjusted according to the change in the spanwise boundary layer thickness, so that the wavelength of each sawtooth maintains the optimal ratio with the boundary layer thickness at the corresponding position, ensuring that the sawtooth can effectively act on the boundary layer throughout the entire spanwise range.

[0092] The wavelength and sawtooth height are adjusted in synergy, and their ratio is adapted to the ratio of wavelength and boundary layer thickness to form a unified perturbation parameter system. This ensures that the sawtooth can generate sufficient perturbation intensity while penetrating deep into the boundary layer, thus breaking up small-scale vortex structures.

[0093] The wavelength design is also adapted to the airflow state after passing through the side edge vortex baffle 102. The characteristics of the airflow boundary layer have changed after being blocked by the baffle. The sawtooth wavelength is optimized for the adjusted boundary layer to ensure that the disturbance effect is accurate and effective.

[0094] The matching of wavelength and boundary layer thickness allows the sawtooth to penetrate deep into the boundary layer and directly act on high-frequency small-scale eddies, resulting in a more direct and significant disturbance effect. This solves the problem that traditional sawtooth cannot effectively act on the boundary layer due to wavelength mismatch.

[0095] The targeted wavelength design enables the sawtooth to precisely disrupt the coherence of high-frequency eddies, efficiently break up small-scale eddies within the boundary layer, and significantly reduce noise energy in the high-frequency band, especially in the critical high-frequency range of 1 to 10 kHz, where the noise reduction effect is outstanding.

[0096] The wavelength design, which is adapted to the boundary layer thickness, avoids insufficient or excessive disturbance. While effectively breaking up small-scale vortices, it does not cause a significant increase in airflow drag, thus balancing noise reduction and aerodynamic efficiency.

[0097] The spanwise wavelength adjustment enables the sawtooth to exert the optimal perturbation effect in different boundary layer thickness regions, ensuring that high-frequency noise can be effectively suppressed throughout the entire spanwise range and avoiding local high-frequency noise bounce.

[0098] According to one embodiment of the present invention, the shape of the saw teeth is an isosceles triangle, trapezoid, sector, staggered shape, or a composite shape composed of at least two of the aforementioned shapes.

[0099] In one embodiment of the present invention, the sawtooth upper edge vortex control structure 104 optimizes the airflow disturbance effect through a variety of sawtooth shapes.

[0100] The sawtooth can take the form of a single shape such as isosceles triangle, trapezoid, fan, or staggered, each shape being aerodynamically optimized to meet the dispersal requirements of high-frequency vortices. The sharp tip of the isosceles triangular sawtooth can generate concentrated disturbances, while the flat top design of the trapezoidal sawtooth provides gentler disturbances. The curved edge of the fan-shaped sawtooth adapts to the airflow trajectory, and the staggered sawtooth can generate multidimensional disturbances.

[0101] The sawtooth pattern can also be formed by combining at least two shapes from isosceles triangles, trapezoids, fan shapes, and staggered shapes to create a composite sawtooth pattern. The combination logic of the composite shapes is determined according to the airflow characteristics. For example, alternating isosceles triangles and trapezoids can take into account the advantages of concentrated and mild disturbances, or small triangular protrusions can be added to the top of the fan-shaped sawtooth pattern to enhance the local disturbance effect.

[0102] Regardless of whether a single or composite shape is used, the shape design of the sawtooth is coordinated with parameters such as height and wavelength to ensure that shape changes do not affect the optimization of the perturbation ratio. This allows the sawtooth to produce a specific perturbation effect while maintaining compatibility with the boundary layer thickness and not reducing the high-frequency noise suppression accuracy.

[0103] The shape of the sawtooth is selected based on the airflow state after passing through the side edge vortex deflector 102. If there are still some medium-sized vortices in the airflow, a sharp-shaped sawtooth can be selected to enhance the disturbance; if the airflow is relatively stable, a mild-shaped sawtooth can be selected for fine disturbance, ensuring that the shape design is specifically designed to address the noise sources in the airflow.

[0104] Different shaped sawtooths can generate different types of disturbances. Single-shaped sawtooths are specifically designed to handle specific types of high-frequency vortices, while composite-shaped sawtooths can cover a wider range of high-frequency vortex structures, thus improving the ability to suppress high-frequency noise in different frequency bands.

[0105] The rational shape design makes the serrations more uniform in disturbing the airflow, avoids excessive or insufficient local disturbances, makes the multi-scale scaling of the shear layer more thorough, the noise spectrum smoother, and further reduces high-frequency noise spikes.

[0106] Different serration shapes have different disturbance intensity and airflow resistance. The appropriate shape can be selected according to the actual application scenario to ensure high-frequency noise reduction effect while controlling airflow resistance within an acceptable range.

[0107] The diverse shape design allows the sawtooth upper edge vortex control structure 104 to adapt to different types of flap side edge aerodynamic environments, expanding the applicability of noise reduction structures. The optimal sawtooth shape can be selected according to the aerodynamic characteristics of a specific aircraft.

[0108] According to one embodiment of the present invention, the three-dimensional gradient leading edge guide structure 100, the side edge vortex baffle 102 and the sawtooth upper edge vortex control structure 104 are connected by surfaces with continuous curvature to form an integrated shape.

[0109] In one embodiment of the present invention, the three-dimensional gradient leading edge guide structure 100, the side edge vortex baffle 102 and the sawtooth upper edge vortex control structure 104 are connected by surfaces with continuous curvature to form an integrated shape.

[0110] The connection surfaces between the three structures all adopt a continuous curvature design, with no sharp corners or abrupt changes. The trailing edge of the flow guide structure and the leading edge of the baffle are connected by a smooth curve, and the upper edge of the baffle is integrated with the root of the sawtooth to form a continuous and smooth integrated aerodynamic profile.

[0111] The integrated shape is compatible with a variety of engineering manufacturing processes. It can be integrally formed through carbon fiber composite lay-up, 3D printing, molding and other methods. The structure has no splicing gaps, has high mechanical continuity, and avoids aerodynamic interference at the splicing points.

[0112] The integrated aerodynamic profile is adapted to the original aerodynamic shape of the flap side edge, without significantly changing the overall aerodynamic characteristics of the flap. Only a locally optimized vortex control and noise reduction structure is formed in the side edge region to ensure that the core aerodynamic performance of the flap, such as lift and drag, is not affected.

[0113] The one-piece molding reduces additional connecting parts, resulting in an extremely lightweight structure. At the same time, the use of the same materials for the three structures further controls the weight and does not increase the overall load on the flaps, thus meeting the aircraft's requirements for lightweight design.

[0114] The continuous curvature of the integrated shape avoids airflow separation and turbulence noise at the junction of multiple structural segments, solves the problem of additional noise generated by multiple structural segments, and makes the noise contribution of the entire noise reduction structure come only from the vortex control noise reduction process, with no additional noise source.

[0115] The integrated structure allows the vortex control effects of the three structures to be seamlessly connected. The velocity field optimization of the flow guide structure, the entrainment and blocking of the baffle, and the high-frequency dispersion of the sawtooth form a continuous vortex control link, which improves the noise reduction effect across the entire frequency band. The overall noise reduction amplitude far exceeds the sum of the individual effects of each structure.

[0116] Integrated molding enhances the mechanical coherence of the structure, eliminates stress concentration caused by gaps, better withstands airflow impacts and vibrations during flight, extends the service life of the structure, and reduces maintenance costs.

[0117] Its integrated shape is compatible with a variety of mature manufacturing processes, resulting in low manufacturing costs and strong mass production capabilities. At the same time, its lightweight design and aerodynamic compatibility with flaps allow the noise reduction structure to be easily integrated into various existing flaps, making it suitable for a wide range of engineering applications.

[0118] According to one embodiment of the present invention, the trailing edge of the side edge vortex baffle 102 is formed as a straight line, a broken line with an upward anti-angle, or a curve with a predetermined curvature change.

[0119] In one embodiment of the present invention, the trailing edge of the side edge vortex-blocking baffle 102 is designed with diverse shapes to adapt to different aerodynamic scenarios and enhance the vortex control and noise reduction effect.

[0120] The trailing edge of the side-edge vortex-blocking baffle 102 is straight, extending horizontally along the span of the flap. The straight edge is smooth and flat, without any bends or protrusions. The straight trailing edge is perpendicular to the baffle body or at a preset angle. The overall structure is simple and the manufacturing process is easy. It can form a stable flow boundary when airflow passes through it, avoiding local vortices caused by complex edge shapes. The length of the straight trailing edge is consistent with the spanwise length of the baffle, covering the entire side-edge shear layer area, ensuring that the blocking effect on the airflow is comprehensive.

[0121] The trailing edge of the side-edge vortex deflector 102 adopts a zigzag shape with an upward inflection angle. The zigzag shape consists of two or more straight segments, with a preset upward inflection angle between adjacent straight segments. The upward inflection angle causes the entire trailing edge to curve upward, forming a specific angle with the baffle body to adapt to the airflow trajectory. The turning points of the zigzag shape are evenly distributed along the spanwise direction or arranged in segments according to aerodynamic requirements, ensuring that the zigzag shape of the trailing edge can act evenly on the flowing airflow without causing local airflow abrupt changes. The trailing edge of the zigzag shape is integrally formed with the baffle body, and the connection part is smoothly transitioned without sharp edges to avoid generating additional noise.

[0122] The trailing edge of the side-edge vortex-blocking baffle 102 features a curved shape with a preset curvature variation. The curvature of the curve changes continuously along the spanwise direction without abrupt changes or inflection points, forming a smooth arc profile. The curvature design adapts to the aerodynamic characteristics of the flap side edge, guiding airflow smoothly along the curve and reducing airflow separation and turbulence generation. The curvature of the trailing edge of the curve has been optimized through aerodynamic simulation to ensure effective blocking of shear layer entrainment at different airflow velocities, while reducing airflow drag. The curvature of the connection between the trailing edge of the curve and the baffle body is continuous, forming an integrated aerodynamic shape and improving the aerodynamic efficiency of the structure.

[0123] The three trailing edge configurations can be flexibly selected based on the aircraft type, flap aerodynamic design, and noise reduction requirements. Regardless of the configuration, the trailing edge is firmly connected to the main body of the side-edge vortex deflector 102, and the overall structural strength meets the airflow impact requirements, preventing deformation or vibration during flight. The trailing edge configuration is coordinated and adapted to the three-dimensional gradient leading edge guide structure and the sawtooth upper edge vortex control structure, ensuring that the three structures form a continuous vortex control link without generating aerodynamic interference.

[0124] The diverse trailing edge morphology allows the side-edge vortex deflector 102 to adapt to the aerodynamic requirements of different types of aircraft (such as civil airliners, drones, and vertical takeoff and landing aircraft) and the airflow characteristics of different flap spanwise directions. A straight trailing edge is suitable for scenarios with high requirements for structural simplicity, an upward-angled zigzag trailing edge is suitable for scenarios that need to enhance the upward deflection of airflow, and a preset curvature curve trailing edge is suitable for scenarios that need to guide the smooth flow of airflow, greatly improving the versatility of the device.

[0125] The flatness of the straight trailing edge can directly block the airflow entrainment path and avoid the merging of small-scale vortices; the upper concave angle broken trailing edge guides the airflow upward through the upper concave angle, further weakening the entrainment force of the shear layer; the preset curvature curve trailing edge guides the airflow to flow smoothly around and reduces airflow separation. All three forms can effectively suppress the formation of large-scale vortices and cut off broadband noise sources from the middle.

[0126] The design of both the dihedral folded trailing edge and the pre-defined curvature curve trailing edge is adapted to the airflow trajectory, reducing airflow separation and turbulence at the trailing edge of the baffle and lowering aerodynamic drag. Compared to the traditional single-shape trailing edge, the diversified shapes can improve the aerodynamic efficiency of the entire noise reduction structure while ensuring vortex control, without affecting the lift performance of the flap.

[0127] The trailing edge morphology works synergistically with the three-dimensional gradient leading edge guide structure and the sawtooth upper edge vortex control structure. The straight trailing edge, in conjunction with the sawtooth structure, enhances the high-frequency vortex dispersion effect; the upward-angled zigzag trailing edge guides the airflow to better enter the sawtooth region; and the preset curvature curve trailing edge echoes the guiding effect of the three-dimensional gradient leading edge, making the airflow smoother. The synergistic effect of the three-segment structure is more significant, and the noise reduction effect across the entire frequency band is better.

[0128] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A noise reduction structure for the side edge of a flap, characterized in that, include: A three-dimensional gradient leading edge guide structure (100) is provided at the front inlet of the side edge of the flap. The outer surface, sweep angle and lateral outward bulge of the three-dimensional gradient leading edge guide structure (100) are all continuously and smoothly varied along the span of the flap. Side edge vortex deflector (102), the side edge vortex deflector (102) is a thin sheet structure, and is disposed downstream of the three-dimensional gradient leading edge guide structure (100). The side edge vortex deflector (102) maintains a preset distance from the trailing edge of the three-dimensional gradient leading edge guide structure (100). The side edge vortex deflector (102) is perpendicular to the flap surface and covers the entire side edge shear layer development area. The sawtooth-shaped upper edge vortex control structure (104) is integrally formed on the upper edge of the side edge vortex deflector (102) away from the flap surface and is continuously distributed along the upper edge of the side edge vortex deflector (102).

2. The noise reduction structure for the side edge of a flap according to claim 1, characterized in that, The height of the side edge vortex deflector (102) is 1 to 3 times the thickness of the local flap side edge.

3. The noise reduction structure for the side edge of a flap according to claim 2, characterized in that, The thickness of the side edge vortex-blocking baffle (102) is 1 to 3 mm.

4. The noise reduction structure for the side edge of a flap according to claim 1, characterized in that, The leading edge of the side edge vortex baffle (102) is smoothly connected to the trailing edge of the three-dimensional gradient leading edge guide structure (100) by means of an arc, spline curve or smooth curve.

5. The noise reduction structure for the side edge of a flap according to claim 1, characterized in that, The sawtooth upper edge vortex control structure (104) includes a plurality of sawtooths continuously distributed along the upper edge of the side edge vortex blocking baffle (102); The ratio of the height of the saw teeth to the wavelength is 2 to 3.

6. The noise reduction structure for the side edge of a flap according to claim 5, characterized in that, The ratio of the wavelength of the sawtooth to the boundary layer thickness at the flap side edge is 1.2 to 2.

7. The noise reduction structure for the side edge of a flap according to claim 5, characterized in that, The serrations are in the shape of an isosceles triangle, trapezoid, sector, or staggered shape, or a composite shape composed of at least two of the aforementioned shapes.

8. The noise reduction structure for the side edge of a flap according to any one of claims 1 to 7, characterized in that, The three-dimensional gradient leading edge guide structure (100), the side edge vortex baffle (102), and the sawtooth upper edge vortex control structure (104) are connected by surfaces with continuous curvature to form an integrated shape.

9. The noise reduction structure for the side edge of a flap according to any one of claims 1 to 7, characterized in that, The trailing edge of the side-edge vortex-blocking baffle is formed as a straight line, a broken line with an upward inflection angle, or a curve with a preset curvature change.

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