Landing gear skin shaping turbulent flow composite noise reduction structure

Abstract

The invention discloses an undercarriage skin shaping turbulent flow composite noise reduction structure, and relates to the technical field of noise control, and the undercarriage skin shaping turbulent flow composite noise reduction structure comprises a shaping cover plate used for blocking an opening of a concave cavity of a first sound source part, a flexible elastic corrugated sleeve used for sleeving a second sound source part, and a skin noise reduction part used for being arranged on a third sound source part; the body-attached noise reduction part comprises two shaping side plates arranged on the leeward side of the third sound source part, the front ends of the two shaping side plates are connected with the two sides of the third sound source part, and the rear ends of the two shaping side plates extend in the flow direction. The projection contour of the shaping side plate on the windward side perpendicular to the incoming flow direction is attached to the projection contour of the third sound source part on the windward side. And the shaping cover plate, the flexible elastic corrugated sleeve and the skin noise reduction piece are in smooth transition with the surface of the undercarriage. The actual noise reduction effect on engineering complex structures is good, the undercarriage structure does not need to be changed, the windward area does not need to be increased, the influence on aerodynamic resistance is small, and the additional weight cost is low.

Description

Technical Field

[0001] This application relates to the field of noise control technology, specifically to a landing gear body-fitting turbulence-reducing composite noise reduction structure. Background Technology

[0002] Landing gear noise is a significant component of external noise during takeoff and landing of civil aircraft, directly impacting airworthiness certification and the acoustic environment around airports. Due to the complex structure of the landing gear and the complex flow phenomena it exhibits during flight, a wide variety of noise-generating sub-components are involved, including tires, main struts, side struts, doors, the cabin body, as well as small and medium-sized accessories such as lamp covers, torsion bars, tow bars, and pipelines. With the continuous tightening of civil aviation noise airworthiness standards, landing gear noise has become a crucial area that must be addressed to reduce noise in large passenger aircraft.

[0003] Currently, typical landing gear noise control methods involved in the research include cavity filling, installing speed brakes, adding spoilers and fairings, and plasma excitation. Among these, fairings have attracted much attention because they can directly isolate airflow from the struts and reduce vortex shedding. Existing typical fairing forms include: first, a large-size, complete fairing located upstream of the landing gear, which isolates / reduces the impact of the incoming flow by shielding the main structure; second, a strut airfoil-like fairing, which uses a closed shell with a tapering tail end to wrap around individual struts and uses the airfoil shape to suppress local vortex shedding; and third, a wire mesh fairing, which uses a porous structure to disrupt the vortex structure and dissipate vortex energy. The above schemes have all achieved certain noise reduction in exploratory tests such as simplified models, providing technical reserves for engineering applications.

[0004] However, existing landing gear noise control methods still have significant shortcomings in their overall performance on complex real-world landing gear configurations: large-size, complete fairings, while significantly reducing noise, are bulky, occupy a lot of space, introduce additional aerodynamic drag, and are prone to interference with the landing gear's retraction and extension movements; rod-type airfoil fairings only target individual rods, offering limited overall noise reduction, and their long dimensions along the flow direction can induce new airfoil self-noise at certain angles of attack; wire mesh fairings lack strength and durability, have high maintenance costs, and their noise reduction effect needs improvement. Furthermore, most noise reduction studies are based on significantly simplified cylindrical or two-dimensional models, lacking consideration of the coupling sound generation mechanisms of multiple components in real-world landing gear. This results in insufficient consideration of the actual noise reduction effect, aerodynamic drag increment, weight cost, structural installation safety, and feasibility of modifying existing products on complex engineering configurations, making it difficult to directly meet the application requirements of specific models. Summary of the Invention

[0005] The purpose of this application is to provide a landing gear conformal shaping and aerodynamic noise reduction composite structure to address the shortcomings of existing landing gear noise reduction methods in terms of actual noise reduction effect, aerodynamic drag increase, weight and cost, structural installation safety, and feasibility of modifying established products in complex engineering configurations.

[0006] The technical solution adopted by this application to solve its technical problem is: The landing gear conformal shaping turbulence composite noise reduction structure includes a shaping cover plate for sealing the cavity opening of the first sound source component, a flexible corrugated sleeve for tightly fitting onto the second sound source component, and a conformal noise reduction component for being installed on the third sound source component. The body-fitting noise reduction component includes two shaping side plates disposed on the leeward side of the third sound source component. The front ends of the two shaping side plates are respectively connected to the two sides of the third sound source component, and the rear ends extend in the flow direction. The projection contour of the shaping side plate on the windward surface perpendicular to the incoming flow direction is aligned with the projection contour of the third sound source component on the windward surface, and the two shaping side plates are parallel to each other or extend outward at 0° to 5° along the incoming flow direction. The shaping cover, the flexible corrugated sleeve, and the body-fitting noise reduction component all smoothly transition to the landing gear surface.

[0007] Furthermore, the length of the shaping side plate along the incoming flow direction is greater than or equal to 1.2 times the length of the short side of the projected profile of the third sound source component on the windward surface perpendicular to the incoming flow direction.

[0008] Furthermore, the rear ends of the two shaping side plates are connected by a shaping tail plate.

[0009] Furthermore, the cavity formed between the two shaping side plates, the shaping tail plate, and the third sound source component is filled with a composite core layer.

[0010] Furthermore, the shaping tail plate is a concave structure recessed in the direction of the third sound source component.

[0011] Furthermore, a concave arc-shaped connecting plate is fixed to the leeward side of the third sound source component, and the two ends of the concave arc-shaped connecting plate are respectively connected to the front ends of the two shaping side plates.

[0012] Furthermore, a concave arc-shaped connecting plate is fixed to the windward side of the third sound source component, and the two ends of the concave arc-shaped connecting plate are respectively connected to the front ends of the two shaping side plates.

[0013] Furthermore, the outer surface of the concave arc-shaped connecting plate, at an angle of 40° to 50° with the incoming flow direction, is provided with a few turbulence units, which protrude 0.5 to 1 mm from the outer surface of the concave arc-shaped connecting plate.

[0014] Furthermore, the shaped side plate includes a metal base layer and a flexible covering layer disposed on its outer surface.

[0015] Furthermore, the first sound source component includes a tire, the second sound source component includes a movable section of the main support rod, and the third sound source component includes a wheel axle, a lamp cover, a steering rod, a fixed section of the main support rod, and a diagonal brace.

[0016] The beneficial effects of this application are: The landing gear conformal shaping and turbulence-induced noise reduction structure provided in this application embodiment uses a shaping cover plate, a flexible corrugated sleeve, and conformal noise reduction components to perform conformal shaping and turbulence-induced noise reduction on different sound source components of the landing gear. This improves the smoothness of the flow, extends the separation distance between the solid structure and the flow in the flow direction, reduces flow separation and shedding vortex energy, and at the same time, it helps to streamline the airflow channels when the airflow passes through the complex configuration of the landing gear. This reduces the intensity of various types of unsteady airflow and their interaction with the structure, thereby achieving effective suppression of landing gear noise.

[0017] Compared to existing technologies, this application does not alter the landing gear structure and is well-suited for existing landing gear products. Based on a close-fitting design, it is small in size and space, avoiding additional aerodynamic drag and noise. It is lightweight, convenient, and practical, and can be directly applied to complex real-world configurations. This addresses the shortcomings of existing landing gear noise reduction methods in terms of actual noise reduction effectiveness, aerodynamic drag increase, weight and cost, structural installation safety, and the feasibility of modifying existing products for complex engineering configurations. Attached Figure Description

[0018] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of the landing gear body-fitting turbulence-reducing composite noise reduction structure provided in the embodiments of this application; Figure 2 This is a schematic diagram of the first type of structure for a body-mounted noise reduction device; Figure 3 This is a schematic diagram of the second structure of the body-fit noise reduction component; Figure 4 This is a schematic diagram of the third type of body-fit noise reduction component; Figure 5 This is a schematic diagram of the fourth structure of the body-fit noise reduction component; Figure 6 This is a diagram showing the basic configuration of the landing gear before noise reduction installation during noise testing. Figure 7It is a noise curve obtained after noise testing of the basic configuration, with a small portion of the noise reduction structure installed, and with the complete noise reduction structure installed.

[0020] Figure label: 1-First sound source component; 2-Shaping cover plate; 3-Second sound source component; 4- Flexible corrugated sleeve; 5-Third sound source component; 6-Patch noise reduction components; 61-Shaping side plate; 611-Metal base layer; 612-Flexible covering layer; 62-Shaped tailplate; 63-Composite core layer; 64- Recessed arc-shaped connecting plate; 65-Concave arc-shaped connecting plate; 66 - Turbulence Unit; 67-Support reinforcement. Detailed Implementation

[0021] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application. Unless otherwise specified, the embodiments and features in the embodiments of this application can be combined with each other.

[0022] In the description of this application, the terms "upper," "lower," "left," "right," "front," "rear," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application. Unless otherwise specified, the above-mentioned orientational descriptions can be flexibly set in actual application, provided that the relative positional relationships shown in the accompanying drawings are satisfied.

[0023] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "set up," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0024] In this paper, the landing gear is taken as the target component, and the side facing the incoming airflow is defined as the windward side, and the side away from the incoming airflow is defined as the leeward side. Along the incoming airflow direction, the side facing the incoming airflow is defined as forward, and the side away from the incoming airflow is defined as aft. The above directional definitions are all based on the landing gear itself as a reference and are independent of the overall attitude of the aircraft.

[0025] During the takeoff and landing phase of an aircraft, the main noise sources of the landing gear consist of three parts: the first noise source 1, the second noise source 3, and the third noise source 5. The first noise source 1 includes the tire, which has a cavity. The second noise source 3 includes the main strut movable section. The third noise source 5 includes the wheel axle, lamp cover, steering rod, main strut fixed section, and diagonal brace.

[0026] See Figure 1 , Figure 2 This application provides a landing gear conforming shaping and turbulence-reducing composite noise reduction structure, including a shaping cover plate 2 for sealing the opening of the cavity of the first sound source component 1, a flexible corrugated sleeve 4 for tightly fitting onto the second sound source component 3, and a conforming noise reduction component 6 for being disposed on the third sound source component 5; the conforming noise reduction component 6 includes two shaping side plates 61 disposed on the leeward side of the third sound source component 5, the front ends of the two shaping side plates 61 are respectively connected to the two sides of the third sound source component 5, and the rear ends extend in the flow direction; the projected contour of the shaping side plate 61 on the windward surface perpendicular to the incoming flow direction fits with the projected contour of the third sound source component 5 on the windward surface, and the two shaping side plates 61 are parallel to each other or extend outward at 0° to 5° along the incoming flow direction; the shaping cover plate 2, the flexible corrugated sleeve 4 and the conforming noise reduction component 6 all smoothly transition with the landing gear surface.

[0027] The shaping cover 2 is a rigid thin plate with uniform thickness and chamfered edges. Its shape matches the contour of the cavity opening on the surface of the first sound source component 1. The shaping cover 2 can be installed at the cavity opening of the first sound source component 1 using countersunk screws or quick-release latches. It not only seals the cavity but also makes the surface of the first sound source component 1 flat, thus shaping the cavity and preventing the vortex inside the cavity from falling off and interacting with external turbulence, thereby eliminating cavity noise. In some embodiments, micro-turbulence units can be added to the outer edge of the cavity. These micro-turbulence units induce turbulence, thereby suppressing large-scale, strongly separated unsteady flow and reducing the spatiotemporal coherence of the flow, further improving noise reduction performance. The micro-turbulence units can be protrusions or strips with a height of 0.5–1 mm and a width of 2–5 mm, arranged equidistantly along the circumference. The micro-turbulence units and the shaping cover 2 can be integrally formed or detachably connected, taking into account maintainability and replaceability.

[0028] The flexible corrugated sleeve 4 is fitted onto the second sound source component 3, allowing it to tightly wrap around the component using its own elasticity, achieving a close-fitting design. Furthermore, to ensure stable coverage of the second sound source component 3, one end of the flexible corrugated sleeve 4 is installed at an appropriate position on the second sound source component 3, and the other end can be installed at an appropriate position on the adjacent third sound source component 5. By designing the flexible corrugated sleeve 4, a turbulence effect can be achieved, thereby reducing the noise of the second sound source component 3. Simultaneously, when the second sound source component 3 expands or contracts, the flexible corrugated sleeve 4 can deform accordingly, avoiding hard interference from structural movements or gaps in structural noise reduction.

[0029] The body-fitting noise reduction component 6 includes two shaped side plates 61. These two side plates 61 are positioned on the leeward side of the third sound source component 5 and arranged opposite each other. The front ends of the shaped side plates 61 are connected to pre-reserved interfaces on the third sound source component 5 via bolts or other fasteners, or can be directly fixed to the third sound source component 5 by strapping or other means. The rear ends of the shaped side plates 61 extend in the flow direction, giving them a tail fin-like layout. The projected contour of the shaped side plate 61 on the windward surface perpendicular to the incoming flow direction matches the corresponding projected contour of the third sound source component 5, thus achieving a body-fitting design between the shaped side plate 61 and the third sound source component 5 and avoiding additional windward area. By using two shaping side plates 61 to conformally shape the third sound source component 5, the noise of the third sound source component 5 can be reduced. Simultaneously, by setting the two shaping side plates 61 to be parallel to each other or extending outwards at 0°–5° along the incoming flow direction, the rear ends of the two shaping side plates 61 are prevented from contracting. This not only reduces the length of the shaping side plates 61 along the incoming flow direction but also suppresses the self-noise induced by the conformal noise reduction component 6. Compared to a structure where the two shaping side plates 61 are parallel to each other, the slightly outward-expanding structure can also reduce the space of the airflow recirculation zone and suppress the occurrence and development of recirculation vortices, thereby further reducing the noise of the conformal noise reduction component 6 itself.

[0030] By smoothly integrating the shaping cover plate 2, the flexible corrugated sleeve 4, and the body-fitting noise reduction component 6 with the landing gear surface, additional interference can be minimized, further improving the noise reduction effect. Specifically, the body-fitting noise reduction component 6 can be made of transparent material in areas such as the landing gear lights and where observation windows are required.

[0031] The landing gear conformal shaping and turbulence-induced noise reduction structure provided in this application embodiment uses a shaping cover plate 2, a flexible corrugated sleeve 4, and conformal noise reduction components 6 to perform conformal shaping and turbulence-induced noise reduction on different sound source components of the landing gear. This improves the smoothness of the flow, extends the separation distance between the solid structure and the flow in the flow direction, weakens the flow separation and shedding vortex energy, and at the same time plays a role in sorting out the airflow channels when the airflow passes through the complex configuration of the landing gear. In this way, it reduces the intensity of various types of unsteady airflow and their interaction with the structure, and achieves effective suppression of landing gear noise.

[0032] Compared to existing technologies, this application does not alter the landing gear structure and is well-suited for existing landing gear products. Based on a close-fitting design, it is small in size and space, avoiding additional aerodynamic drag and noise. It is lightweight, convenient, and practical, and can be directly applied to complex real-world configurations. This addresses the shortcomings of existing landing gear noise reduction methods in terms of actual noise reduction effectiveness, aerodynamic drag increase, weight and cost, structural installation safety, and the feasibility of modifying existing products for complex engineering configurations.

[0033] The noise reduction structure of this application can be made of composite materials, adopts a lightweight design, and the total thickness of the base structure can be 0.5 to 1 mm or even thinner. The modular and easy-to-disassemble design allows for flexible installation and has good engineering practicality.

[0034] In some embodiments, the length of the shaping side plate 61 along the incoming flow direction is greater than or equal to 1.2 times the length of the short side of the projected profile of the third sound source 5 on the windward surface perpendicular to the incoming flow direction. Accordingly, this length setting allows the rear end of the shaping side plate 61 to naturally extend downstream of the wake reattachment zone of the third sound source 5, which can constrain the vortex shedding scale in advance and reduce the vortex shedding intensity; sufficient flow direction dimensions provide a gradual diffusion space for the airflow, avoid the instantaneous reverse pressure gradient caused by the sudden expansion of the trailing edge, and significantly suppress low-frequency narrowband noise.

[0035] In some embodiments, see Figure 2 , Figure 3 , Figure 4 The rear ends of the two shaping side plates 61 are connected by a shaping tail plate 62. Correspondingly, by setting the shaping tail plate 62, the rear ends of the two shaping side plates 61 are connected into a closed structure, significantly enhancing structural rigidity and suppressing flutter and edge whistling under high-speed airflow. The shaping tail plate 62 can also block lateral crosstalk between the two wakes, weakening the collision and recoupling of the vortex shearing, further reducing noise. Simultaneously, the shaping tail plate 62 provides a stable back pressure surface for the reattached airflow, causing the separation shear layer to rise earlier and dissipate more quickly, further reducing the conversion of turbulent kinetic energy into acoustic energy, achieving the effect of no increase in drag and noise reduction gain.

[0036] In some embodiments, see Figure 2 , Figure 3 , Figure 4 The cavity formed by the two shaping side plates 61, the shaping tail plate 62, and the third sound source component 5 is filled with a composite core layer 63. The composite core layer 63 is mainly composed of foam, honeycomb, reinforced, or composite structures. Accordingly, by setting the composite core layer 63, the cavity is transformed from a cavity resonator into a constrained damping-sound-absorbing composite, suppressing structural vibration and cavity resonance while maintaining the aerodynamic shape, further improving the noise reduction effect.

[0037] In some embodiments, see Figure 2 , Figure 4 The shaping tail plate 62 is a concave structure recessed towards the third sound source component 5. Accordingly, by making the shaping tail plate 62 a concave structure, the volume of the cavity formed between the two shaping side plates 61, the shaping tail plate 62 and the third sound source component 5 can be reduced, thereby reducing the filling amount of the composite core layer 63, reducing the structural weight, and reducing the effect of the tail detachment vortex of the body-fit noise reduction component 6 on its structural surface; at the same time, the recessed part forms a local static pressure zone that can capture and dissipate turbulent kinetic energy and reduce the coherence length of the tail vortex.

[0038] In some embodiments, see Figure 2 , Figure 3 , Figure 4 A concave arc-shaped connecting plate 64 is fixed to the leeward side of the third sound source component 5. Both ends of the concave arc-shaped connecting plate 64 are connected to the front ends of the two shaped side plates 61, respectively. The concave arc-shaped connecting plate 64 is a rearwardly recessed arc-shaped connecting plate, and a flexible composite material gasket is provided between it and the leeward surface of the third sound source component 5. The flexible composite material gasket serves to buffer the load and enhance the fit. The concave arc-shaped connecting plate 64 can be fixedly connected to the third sound source component 5 using bolts or other fasteners. Both ends of the concave arc-shaped connecting plate 64 can be welded to the front ends of the two shaped side plates 61 or integrally formed. Accordingly, the concave arc-shaped connecting plate 64 is used to reliably connect the front ends of the two shaped side plates 61 to the third sound source component 5.

[0039] In some embodiments, see Figure 3 , Figure 4 , Figure 5 A concave arc-shaped connecting plate 65 is fixed to the windward side of the third sound source component 5. Both ends of the concave arc-shaped connecting plate 65 are connected to the front ends of two shaping side plates 61, respectively. The concave arc-shaped connecting plate 65 is a forward-recessed arc-shaped connecting plate, and a flexible composite material gasket is provided between it and the windward surface of the third sound source component 5. The flexible composite material gasket serves to buffer the load and enhance the fit. The concave arc-shaped connecting plate 65 can be fixedly connected to the third sound source component 5 using bolts or other fasteners. Both ends of the concave arc-shaped connecting plate 65 can be bolted, welded, or integrally formed to the front ends of the two shaping side plates 61. Accordingly, by setting the concave arc-shaped connecting plate 65, it is not only used to shape the windward surface of the third sound source component 5 to reduce noise, but also to reliably connect the front ends of the two shaping side plates 61 to the third sound source component 5.

[0040] The concave arc-shaped connecting plate 65 may include one or two. When there are two concave arc-shaped connecting plates 65, the two concave arc-shaped connecting plates 65 are spaced apart along the incoming flow direction and their ends are connected accordingly. The concave arc-shaped connecting plate 65 located on the inner side can be fixedly connected to the third sound source component 5 by fasteners such as bolts. A composite core layer 63 can be filled between the two concave arc-shaped connecting plates 65.

[0041] In some embodiments, small connecting blocks are provided between the connection positions of the concave arc-shaped connecting plate 65 and the shaping side plate 61, and the corresponding small connecting blocks are fixedly connected by riveting or bolts. At the same time, in order to avoid the formation of reverse airflow steps or large gaps at the connection positions of the concave arc-shaped connecting plate 65 and the shaping side plate 61, the concave arc-shaped connecting plate 65 and the shaping side plate 61 are arranged with an overlap, and the concave arc-shaped connecting plate 65 is located on the outside. The outer surface of the overlap position is consistent with the shape of the shaping component of the noise reduction part to be designed, and the inner surface is in contact with the surface of the third sound source component 5.

[0042] In some embodiments, see Figure 4 A small disturbance flow unit 66 is provided on the outer surface of the concave arc-shaped connecting plate 65 at an angle of 40° to 50° with the incoming flow direction. The disturbance flow unit 66 protrudes 0.5 to 1 mm from the outer surface of the concave arc-shaped connecting plate 65. The disturbance flow unit 66 can be a protrusion or a ridge, and the small disturbance flow units 66 are arranged at intervals. Accordingly, by setting the small disturbance flow units 66, turbulence is induced by the micro-turbulence units, thereby suppressing large-scale, strongly separated unsteady flow and reducing the spatiotemporal coherence of the flow, further improving noise reduction performance.

[0043] In some embodiments, see Figure 5 Both the shaping side plate 61 and the concave arc-shaped connecting plate 65 include a metal base layer 611 and a flexible covering layer 612 on their outer surface. Supporting ribs 67 can be provided between the metal base layers 611 of the two shaping side plates 61 to increase strength and rigidity. Correspondingly, the metal base layer 611 ensures that the shaping side plate 61 has sufficient bending stiffness and impact resistance, capable of withstanding high-frequency aerodynamic pulses during takeoff and landing without permanent deformation. The flexible covering layer 612 on the outer surface can be a flexible layer such as felt, which can instantly convert wall turbulence energy into frictional heat, forming a hard support-soft dissipation synergistic mechanism, further improving noise reduction.

[0044] The landing gear body-fitting turbulence-reducing composite noise reduction structure provided in this application has been the subject of large-scale wind tunnel testing and verification on a full-size high-fidelity landing gear model for a specific equipment application. The results show that the design can achieve significant noise reduction. Test photos and typical results are shown below. Figure 6 , Figure 7 As shown. Among them, Figure 6 The diagram shows the basic configuration of the landing gear before the noise reduction installation, during noise testing. Both configurations with partial and complete noise reduction installations were tested under the same conditions and setup, with the test status being similar to... Figure 6 As is consistent, no additional drawings are attached to this application. Figure 7 The figures shown are noise curves obtained under the same test conditions for the basic configuration, the installation of a small number of noise reduction structures (such as noise reduction structures at the tire cavity, axle, lamp cover and steering rod), and the installation of a complete noise reduction structure (such as noise reduction structures at all sound source components).

[0045] from Figure 7 The following conclusions can be drawn: When the noise reduction scheme proposed in this application is used in a real-scale high-fidelity take-off and landing structure, it can achieve significant noise reduction effect; among them, the design with a small number of noise reduction structures can achieve a comprehensive noise reduction effect of 3-4dB in a wide frequency band, and the design with a complete noise reduction structure can further improve the noise reduction performance, with a comprehensive suppression of 6-7dB; the influence of the completeness of the noise reduction design components on the noise reduction effect also confirms the necessity of adopting a multi-component, multi-scheme noise reduction design.

[0046] The above are merely specific embodiments of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application.

Claims

1. A landing gear skin shaping and disturbing composite noise reduction structure, characterized in that, The application relates to a sound source cover plate (2) for sealing the opening of a first sound source part (1), a flexible and elastic corrugated sleeve (4) for tightly sleeving a second sound source part (3), and a skin noise reduction part (6) arranged on a third sound source part (5). The skin noise reduction part (6) comprises two shaping side plates (61) arranged on the leeward side of the third sound source part (5), the front ends of the two shaping side plates (61) are connected with the two sides of the third sound source part (5) respectively, and the rear ends extend along the flow direction. The projection profile of the shaping side plate (61) on the windward surface perpendicular to the flow direction is matched with the projection profile of the third sound source part (5) on the windward surface, and the two shaping side plates (61) are parallel to each other or outwardly expanded by 0-5 degrees along the flow direction. The shaping cover plate (2), the flexible and elastic corrugated sleeve (4) and the skin noise reduction part (6) are smoothly connected with the surface of the landing gear.

2. The undercarriage conformal shaping spoiler composite noise-reducing structure of claim 1, wherein, The length of the shaping side plate (61) along the flow direction is greater than or equal to 1.2 times the length of the short side of the projection profile of the third sound source part (5) on the windward surface perpendicular to the flow direction.

3. The undercarriage conformal shaping spoiler composite noise-reducing structure of claim 1, wherein, The rear ends of the two shaping side plates (61) are connected through a shaping tail plate (62).

4. The undercarriage conformal shaping spoiler composite noise-reducing structure of claim 3, wherein, The cavity surrounded by the two shaping side plates (61), the shaping tail plate (62) and the third sound source part (5) is filled with a composite core layer (63).

5. The undercarriage conformal shaping spoiler composite noise-reducing structure of claim 4, wherein, The shaping tail plate (62) is an inner recess structure which is recessed towards the third sound source part (5).

6. The landing gear conformal shaping spoiler composite noise-reducing structure according to claim 1, 2, 3, 4 or 5, characterized in that, The leeward side of the third sound source part (5) is fixed with a rear recessed arc-shaped connecting plate (64), and the two ends of the rear recessed arc-shaped connecting plate (64) are connected with the front ends of the two shaping side plates (61) respectively.

7. The undercarriage conformal shaping spoiler composite noise-reducing structure of claim 1, 2, 3, 4, or 5, wherein, The windward side of the third sound source part (5) is fixed with a front recessed arc-shaped connecting plate (65), and the two ends of the front recessed arc-shaped connecting plate (65) are connected with the front ends of the two shaping side plates (61) respectively.

8. The undercarriage conformal shaping spoiler composite noise-reducing structure of claim 7, wherein, The outer surface of the front recessed arc-shaped connecting plate (65) and the region with an angle of 40-50 degrees with the flow direction are provided with a plurality of flow disturbing units (66), and the flow disturbing units (66) protrude the outer surface of the front recessed arc-shaped connecting plate (65) by 0.5-1 mm.

9. The landing gear conformal shaping spoiler composite noise-reducing structure of claim 1, 2, 3, 4, or 5, wherein, The shaping side plate (61) comprises a metal base layer (611) and a flexible covering layer (612) arranged on the outer surface thereof.

10. The undercarriage conformal shaping spoiler composite noise-reducing structure of Claim 1, wherein, The first sound source part (1) comprises a tire, the second sound source part (3) comprises a main support rod movable section, and the third sound source part (5) comprises an axle, a lampshade, a steering rod, a main support rod fixed section and an inclined support rod.

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