A structure for controlling cavity wind-induced noise based on the silent flight characteristics of an owl

Abstract

The application discloses a structure for controlling cavity wind-induced vibration noise based on the silent flight characteristics of owls, which is arranged on the front edge of an automobile sunroof or a B column of an automobile side window; the structure for controlling cavity wind-induced vibration noise comprises a concave structure; the concave structure comprises a surface ridge structure, a flow direction structure and a hem curve structure; the application arranges a novel structure for suppressing cavity wind-induced vibration noise based on the silent flight characteristics of owls at a position upstream of a cavity opening, reduces the spanwise pressure correlation at the opening front edge, makes the boundary layer at the trailing edge position fluctuate along the spanwise direction, and thickens the boundary layer thickness at the trailing edge, so that the low-frequency wind-induced vibration noise in the cavity and the wind noise at the opening are effectively suppressed, and the user experience is optimized.

Description

Technical Field

[0001] This invention relates to the field of wind vibration noise control technology, specifically a structure for controlling cavity wind vibration noise based on the silent flight characteristics of owls. Background Technology

[0002] When airflow passes through a cavity, it induces high-intensity wind-induced vibration noise within the cavity, with sound pressure levels generally exceeding 120 dB. This can not only cause fatigue damage to mechanical structures but also cause severe discomfort to passengers in the cabin. Therefore, how to effectively control this wind-induced vibration noise has become a fundamental issue in fields such as aviation, high-speed rail, and automobiles.

[0003] To suppress the adverse effects of wind-induced vibration noise, two main approaches are currently employed: active control and passive control. Active control research primarily focuses on open-loop control, such as active jets and active deflectors. While these active methods effectively suppress wind-induced vibration noise, their practical applications are limited by factors such as the control bandwidth and energy consumption of the actuators. Currently, passive control is more commonly used, including deflectors, adding sub-cavities within the air cavity, and altering the shape of the leading and trailing edges. Although many studies have shown that disrupting the formation mechanism of wind-induced vibration noise can suppress its sound pressure amplitude, its effectiveness is limited. Therefore, finding an efficient and practical solution remains a significant challenge. Summary of the Invention

[0004] The purpose of this invention is to provide a structure for controlling cavity wind vibration noise based on the silent flight characteristics of owls. The structure for controlling cavity wind vibration noise is arranged on the front edge of a car sunroof or the B-pillar of a car side window.

[0005] The structure for controlling cavity wind vibration noise includes a concave structure;

[0006] The concave structure includes a surface ridge structure, a flow structure, and a collar curve structure;

[0007] The flow structure is a concave structure and is located upstream of the front edge of the cavity opening;

[0008] The cross section of the flow structure is a NACA0012 airfoil suction surface;

[0009] The collar edge curve structure is a sinusoidal curve structure;

[0010] The collar curve structure is set at the interface between the flow structure and the cavity cover plate and is in contact with the front edge of the cavity opening, so that the surface of the flow structure undulates in the expansion direction, thereby forming a ridge structure on the surface of the flow structure.

[0011] Furthermore, the spanwise length of the flow structure is equal to the length of the sunroof opening.

[0012] Furthermore, the width of the flow structure in the direction of airflow is equal to the width of the cavity opening.

[0013] Furthermore, the windward side and the side facing the airflow of the concave structure are straight lines.

[0014] Furthermore, the collar curve structure exhibits sinusoidal fluctuations with a wavelength range of [0.12c, 0.30c]; where c is the opening width of the cavity.

[0015] Furthermore, the distance c between the collar curve and the windward side of the flow structure s As shown below:

[0016]

[0017] In the formula, z is the spanwise coordinate on the concave structure; λ is the wavelength of the collar curve structure (1); and a is the amplitude of the cosine function.

[0018] Furthermore, the concave structure forms a vortex at the cavity opening, and this vortex is discontinuous in the spanwise direction.

[0019] The technical effects of this invention are undeniable. This invention can disrupt the spanwise correlation of airflow at the leading edge of the cavity opening, and can divide the tubular vortices that fall off at the leading edge into spanwise discontinuous horseshoe vortices, raising the height of the shear layer, and causing the boundary layer thickness at the trailing edge of the cavity to fluctuate along the spanwise and be thickened. This can effectively suppress wind vibration noise in the cavity and reduce wind noise near the opening. It is low in cost and has a good noise reduction effect.

[0020] This invention employs a novel structure, based on the silent flight characteristics of an owl, to suppress wind-induced vibration noise in a cavity by arranging such a structure upstream of the cavity opening. This reduces the spanwise pressure correlation at the leading edge of the opening, causes the boundary layer at the trailing edge to fluctuate along the spanwise direction, and increases the thickness of the boundary layer at the trailing edge. As a result, low-frequency wind-induced vibration noise within the cavity and wind noise at the opening are effectively suppressed, thus optimizing the user experience. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of a typical open cavity structure in the prior art;

[0022] Figure 2 This is a schematic diagram of a biomimetic structure based on the silent flight characteristics of an owl to suppress cavity wind vibration noise according to an embodiment of the present invention.

[0023] Figure 3 This is a schematic diagram of the flow cross-sectional profile of the biomimetic structure at two spanwise positions according to an embodiment of the present invention;

[0024] Figure 4 This is a comparison diagram of the collar curve of the bionic knot according to an embodiment of the present invention and the front edge of a general cavity;

[0025] Figure 5 This is a comparison diagram of the biomimetic structure according to an embodiment of the present invention and the vortex in a general cavity;

[0026] Figure 6 This is a comparison diagram of the boundary layer thickness at the trailing edge of the biomimetic structure according to an embodiment of the present invention and a general cavity;

[0027] Figure 7 This is a noise comparison diagram between a biomimetic structure according to an embodiment of the present invention and a general cavity, wherein... Figure 7 (a) The incoming flow velocity is 15 m / s. Figure 7 The incoming flow velocity in (b) is 20 m / s, and the incoming flow velocity in (c) is 25 m / s;

[0028] Figure 8 This is a schematic diagram of a noise reduction structure on a car side window.

[0029] In the figure, there is a collar curve structure 1 and a surface ridge structure 2. Detailed Implementation

[0030] The present invention will be further described below with reference to embodiments, but it should not be construed that the scope of the present invention is limited to the following embodiments. Various substitutions and modifications made based on ordinary technical knowledge and common practices in the art without departing from the above-described technical concept of the present invention should be included within the scope of protection of the present invention.

[0031] Example 1:

[0032] See Figures 1 to 8 A structure for controlling cavity wind vibration noise based on the silent flight characteristics of owls, wherein the structure for controlling cavity wind vibration noise is arranged on the front edge of the sunroof of a car or the B-pillar of the side window of a car.

[0033] The structure for controlling cavity wind vibration noise includes a concave structure;

[0034] The concave structure includes a surface ridge structure 2, a flow structure, and a collar curve structure 1;

[0035] The flow structure is a concave structure and is located upstream of the front edge of the cavity opening;

[0036] The cross section of the flow structure is a NACA0012 airfoil suction surface;

[0037] The cross-sectional parameters of the suction surface of the NACA0012 airfoil are shown below:

[0038] x / c y / c x / c y / c 0.0050 0.0122 0.325 0.0599 0.0100 0.0170 0.35 0.0595 0.02 0.0236 0.375 0.0588 0.03 0.0284 0.4 0.0580 0.04 0.0323 0.425 0.0569 0.05 0.0355 0.45 0.0558 0.06 0.0383 0.475 0.0544 0.08 0.0430 0.5 0.0529 0.10 0.0469 0.55 0.0495 0.12 0.0499 0.6 0.0456 0.14 0.0524 0.65 0.0413 0.16 0.0544 0.7 0.0366 0.18 0.0560 0.75 0.0315 0.20 0.0574 0.8 0.0262 0.225 0.0586 0.85 0.0205 0.25 0.0594 0.9 0.0145 0.275 0.0599 0.95 0.0080 0.3 0.0600 1.00 0.0013

[0039] The collar curve structure 1 is a sinusoidal curve structure;

[0040] The collar curve structure 1 is set at the interface between the flow structure and the cavity cover plate and is in contact with the front edge of the cavity opening, so that the surface of the flow structure undulates in the expansion direction, thereby forming a surface ridge structure 2 on the surface of the flow structure.

[0041] The spanwise length of the flow structure is equal to the length of the sunroof opening of the car.

[0042] The width of the flow structure in the direction of airflow is equal to the width of the cavity opening.

[0043] The windward side and the side facing the airflow of the concave structure are straight lines.

[0044] The collar curve structure 1 exhibits sinusoidal oscillation with a wavelength range of [0.12c, 0.30c]; c is the opening width of the cavity.

[0045] The distance c between the collar curve and the windward side of the flow structure s As shown below:

[0046]

[0047] In the formula, z is the spanwise coordinate of the concave structure, specifically ranging from 0 mm to 240 mm (240 mm is the spanwise length of the concave structure, which is also the length of the cavity opening). The starting point of z is the starting point of the collar curve, i.e., the endpoint of the side boundary line between the concave structure and the cover plate; λ is the wavelength of collar curve structure 1; a is the amplitude of the cosine function, representing the amplitude of the collar curve. In this case, a = 0.06c (c is the width of the cavity opening).

[0048] The concave structure forms a vortex at the cavity opening, and this vortex is discontinuous in the spanwise direction.

[0049] Example 2:

[0050] A novel structure for suppressing cavity wind vibration noise based on the silent flight characteristics of owls includes: a recess located upstream of the leading edge of the cavity opening;

[0051] The pit has the following characteristics:

[0052] The sinusoidal collar curve is located at the interface between the recess and the cavity cover plate, close to the front edge of the cavity opening;

[0053] A surface ridge structure is located on the surface of the pit.

[0054] The profile of each flow section of the recess conforms to the cross-sectional parameters of the NACA0012 airfoil suction surface. The spanwise length of the recess is equal to the length of the cavity opening. In the direction of airflow, the width of the recess is equal to the width of the cavity opening. The windward side of the recess is a straight line, and the two sides in the direction of airflow are also straight lines. The leading edge near the cavity opening is the sinusoidal leading edge curve.

[0055] The sinusoidal collar curve is a sinusoidal curve that satisfies formula (1) and is located close to the leading edge of the opening. The wavelength of the sinusoidal curve is recommended to be between 0.12c and 0.30c, and the amplitude of the sinusoidal curve is 0.06c. The distance between the sinusoidal collar curve and the windward side of the recess is the chord length of the recess. The chord length is continuously varying in the spanwise direction, satisfying formula (1), which also causes the surface ridge structure to form on the surface inside the recess.

[0056]

[0057] In the formula, c s is the chord length of the concave section, c is the average chord length of the concave section, which is equal to the opening width of the cavity, z is the spanwise position, the origin of the coordinate system is shown in Figure (a), and λ is the wavelength of the sinusoidal collar curve. In this invention, λ can be any value, but in this case, the optimal range is between 12 mm and 30 mm.

[0058] The surface ridge structure is formed because the chord length of the pit changes in the spanwise direction according to the leading edge curve of the sinusoidal shape, and the cross-sectional shape of the pit needs to meet the cross-sectional parameters of the NACA0012 airfoil suction surface. This causes the surface of the pit to fluctuate up and down in the spanwise direction, forming the surface ridge structure.

[0059] Example 3:

[0060] A structure for suppressing cavity wind vibration noise based on the silent flight characteristics of owls includes: a recess located upstream of the cavity opening; the recess has a surface ridge structure; Figure 3 The flow cross-sectional shape shown and Figure 4 The collar curve is shown in a sinusoidal shape.

[0061] The above technical solution, through Figure 1 The biomimetic structure with a concave shape is set at the upstream position of the opening of the general cavity shown, thereby reducing the spanwise pressure correlation at the leading edge of the opening, causing the boundary layer at the trailing edge to fluctuate along the spanwise direction, and increasing the thickness of the boundary layer at the trailing edge. This effectively suppresses the low-frequency wind vibration noise in the cavity and the wind noise at the opening, thus optimizing the user experience.

[0062] The biomimetic structure of this invention is based on three main features of the wings of a barn cat: (1) a serrated collar that can comb airflow; (2) fine downy hairs on the surface of the wings; and (3) a trailing edge with tassel-like feathers.

[0063] The biomimetic structure of this invention, as a passive structure for suppressing wind noise within a cavity, exhibits excellent noise reduction capabilities across a wide range of speeds and frequencies, significantly improving noise pollution within the cavity. The cavity-type sandwich metamaterial structure of this invention can be widely applied in various fields, such as wind noise suppression in automotive passenger compartments, wind noise suppression when aircraft landing gear is lowered, and noise suppression when aircraft missile bays are opened.

[0064] Figure 2 The biomimetic structure can be made of metal or plastic with a certain strength. In addition, other suitable materials can be selected according to the actual application.

[0065] Figure 2 The biomimetic structure is arranged in Figure 1 The upstream position of a typical open cavity, and Figure 2 The biomimetic structure of the sinusoidal collar edge and the adjacent Figure 1 The leading edge of a typical open cavity.

[0066] Figure 2 The biomimetic structure is placed in the form of a recess.

[0067] The inventors compared the flow field characteristics of the biomimetic structure of this invention with those of existing conventional open cavities. Flow field simulations were performed for both structures, such as... Figure 5 As shown, the vortex in the biomimetic structure of this invention is discontinuous in the spanwise direction at the cavity opening; while the vortex in a typical open cavity is continuous and tubularly distributed. This indicates that under the same inflow conditions, the spanwise correlation of a typical open cavity is very strong, while the spanwise correlation of the biomimetic structure of this invention is disrupted.

[0068] Through simulation, the inventors studied the influence of the structural parameter wavelength on the spanwise boundary layer thickness at the trailing edge of the cavity opening. For example... Figure 6 As shown, the biomimetic structure of this invention enables the boundary layer at the trailing edge to undulate in the spanwise direction and significantly increases the thickness of the boundary layer, thereby achieving the effect of suppressing intracavity noise. Figure 7 As shown, the biomimetic structure of the present invention can significantly suppress wind noise in a typical cavity under operating conditions of 15m / s, 20m / s and 25m / s, which indicates that the present invention can effectively suppress noise in a cavity over a wide frequency and speed range.

[0069] Example 4:

[0070] A structure for controlling cavity wind vibration noise based on the silent flight characteristics of owls, wherein the structure for controlling cavity wind vibration noise is arranged on the front edge of a car sunroof or the B-pillar of a car side window;

[0071] The structure for controlling cavity wind vibration noise includes a concave structure;

[0072] The concave structure includes a surface ridge structure 2, a flow structure, and a collar curve structure 1;

[0073] The flow structure is a concave structure and is located upstream of the front edge of the cavity opening;

[0074] The cross section of the flow structure is a NACA0012 airfoil suction surface;

[0075] The collar curve structure 1 is a sinusoidal curve structure;

[0076] The collar curve structure 1 is set at the interface between the flow structure and the cavity cover plate and is in contact with the front edge of the cavity opening, so that the surface of the flow structure undulates in the expansion direction, thereby forming a surface ridge structure 2 on the surface of the flow structure.

[0077] Example 5:

[0078] A structure for controlling cavity wind vibration noise based on the silent flight characteristics of owls is described in Example 4, wherein the spanwise length of the flow structure is equal to the length of the sunroof opening of a car.

[0079] Example 6:

[0080] A structure for controlling cavity wind vibration noise based on the silent flight characteristics of owls is described in Embodiment 4. The width of the flow structure in the direction of airflow is equal to the width of the cavity opening.

[0081] Example 7:

[0082] A structure for controlling cavity wind vibration noise based on the silent flight characteristics of owls is described in Example 4, wherein the windward side and the side with the airflow of the concave structure are straight lines.

[0083] Example 8:

[0084] A structure for controlling cavity wind vibration noise based on the silent flight characteristics of owls is described in Example 4. The collar curve structure 1 exhibits sinusoidal fluctuations with a wavelength range of [0.12c, 0.30c], where c is the opening width of the cavity.

[0085] Example 9:

[0086] A structure for controlling cavity wind vibration noise based on the silent flight characteristics of owls is described in Example 4. The main details are provided in Example 4, where the distance c between the collar curve and the windward side of the flow structure is... s As shown below:

[0087]

[0088] In the formula, z is the spanwise coordinate on the concave structure; λ is the wavelength of the collar curve structure 1; a is the amplitude of the cosine function; and c is the opening width of the cavity.

[0089] Example 10:

[0090] A structure for controlling cavity wind vibration noise based on the silent flight characteristics of owls is described in Example 4. The concave structure forms a vortex at the cavity opening, and the vortex is discontinuous in the spanwise direction.

Claims

1. A structure for controlling cavity wind vibration noise based on the silent flight characteristics of owls, characterized in that: The structure for controlling cavity wind vibration noise is arranged on the front edge of the car sunroof or the B-pillar of the car side window. The structure for controlling cavity wind vibration noise includes a concave structure; The concave structure includes a surface ridge structure (2), a flow structure, and a collar curve structure (1); The flow structure is a concave structure and is located upstream of the front edge of the cavity opening; The cross section of the flow structure is a NACA0012 airfoil suction surface; The collar curve structure (1) is a sinusoidal curve structure; The collar curve structure (1) is set at the interface between the flow structure and the cavity cover plate and is in contact with the front edge of the cavity opening, so that the surface of the flow structure undulates in the expansion direction, thereby forming a surface ridge structure (2) on the surface of the flow structure.

2. The structure for controlling cavity wind vibration noise based on the silent flight characteristics of owls according to claim 1, characterized in that: The spanwise length of the flow structure is equal to the length of the sunroof opening of the car.

3. The structure for controlling cavity wind vibration noise based on the silent flight characteristics of owls according to claim 1, characterized in that: The width of the flow structure in the direction of airflow is equal to the width of the cavity opening.

4. The structure for controlling cavity wind vibration noise based on the silent flight characteristics of owls according to claim 1, characterized in that: The windward side and the side facing the airflow of the concave structure are straight lines.

5. A structure for controlling cavity wind vibration noise based on the silent flight characteristics of an owl, as described in claim 1, characterized in that: The collar curve structure (1) exhibits sinusoidal oscillation with a wavelength range of [0.12c, 0.30c]; c is the opening width of the cavity.

6. The structure for controlling cavity wind vibration noise based on the silent flight characteristics of owls according to claim 1, characterized in that: The distance c between the collar curve and the windward side of the flow structure s As shown below: In the formula, z is the spanwise coordinate on the concave structure; λ is the wavelength of the collar curve structure (1); a is the amplitude of the cosine function; and c is the opening width of the cavity.

7. The structure for controlling cavity wind vibration noise based on the silent flight characteristics of owls according to claim 1, characterized in that: The concave structure forms a vortex at the cavity opening, and this vortex is discontinuous in the spanwise direction.

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