Omnidirectional modularized wind tunnel standard sound source

Abstract

The invention relates to the technical field of wind tunnel tests, in particular to an omni-directional modular wind tunnel standard sound source. The omni-directional modular wind tunnel standard sound source comprises a sound production module, the sound production module comprises at least two loudspeakers, at least two sound guide pressing rings and a middle partition plate, the at least two loudspeakers are oppositely arranged and are symmetrical in the axial direction of the sound production module, and the loudspeakers are used for outputting sound waves; the at least two sound guide pressing rings are arranged at intervals, and the at least two sound guide pressing rings are symmetrically arranged between the at least two loudspeakers; the middle partition plate is arranged between the at least two sound guide pressing rings, one end of each sound guide pressing ring is connected with the loudspeaker, and the other end of each sound guide pressing ring is separated from the middle partition plate; the sound guide pressing ring and the middle partition plate can form a guide sound cavity to transmit sound waves output by the loudspeaker. Therefore, a sound wave propagation path is optimized, internal reflection is reduced, and sound waves can be uniformly and stably distributed in the circumferential direction and the polar angle direction so as to realize a far-field omnidirectional sound field.

Description

Technical Field

[0001] This application relates to the field of wind tunnel testing technology, and in particular to an omnidirectional modular wind tunnel standard sound source. Background Technology

[0002] When conducting acoustic testing in aeroacoustic wind tunnels, factors such as wind tunnel shear layers, sound scattering from the model and data acquisition equipment supports, wall reflections, and reverberation can interfere with the accuracy of the data. Therefore, it is necessary to use standard sound sources to conduct tests, optimize experimental procedures, and provide a basis for data correction. The requirements for standard sound sources are, on the one hand, the ability to generate a high-precision omnidirectional spherical sound field (covering a ±60° polar angle range), and on the other hand, the necessary sound power to simulate various test signals such as pure tones, broadband, and pulses.

[0003] Currently, the polyhedral sound sources and mid-to-high frequency duct-type volumetric sound sources commonly used in architectural acoustics cannot be used in fluid scenarios; while among wind tunnel-specific sound sources, loudspeaker-type sound sources installed against the wall can achieve broadband or pure tone noise but have poor directivity, laser-induced plasma-type sound sources are used for mid-to-high frequency sound field testing but have complex structures and high costs, and micro-jet-type sound sources are used to generate broadband signals but require an additional air source.

[0004] To reduce the impact of airflow, existing technologies have optimized standard sound sources such as loudspeakers in wind tunnels, but significant shortcomings remain. For example, when the cylindrical shape of the standard sound source is perpendicular to the incoming flow direction and the sound-transmitting parts are not specially treated, vortices and cavity noise are easily generated under flow conditions, interfering with sound field propagation. Furthermore, when the standard sound source uses a streamlined shell but is not optimized for omnidirectionality, the shell itself will generate scattering, increasing directivity error and making it difficult to form an ideal spherical sound field. Moreover, when only the circumferential directivity of the cylindrical cross-section of the sound source is optimized, the directivity performance in the polar angle direction along the flow direction is poor, and the influence of the loudspeaker's back cavity on directivity is ignored. In addition, the high- and low-frequency crossover combination scheme of the loudspeaker has shortcomings in practical applications, leading to deterioration of far-field directivity.

[0005] Therefore, in view of this situation, there is a need to provide an omnidirectional modular wind tunnel standard sound source to at least partially solve the existing problems. Summary of the Invention

[0006] The summary of this application introduces a series of simplified concepts, which will be further explained in detail in the detailed description section. This summary is not intended to limit the key features and essential technical features of the claimed technical solution, nor is it intended to determine the scope of protection of the claimed technical solution.

[0007] This application provides an omnidirectional modular wind tunnel standard sound source, including a sound-generating module, the sound-generating module comprising: At least two loudspeakers are arranged opposite each other and are symmetrical about each other along the axial direction of the sound-generating module. The loudspeakers are used to output sound waves. At least two sound guide rings are provided, the at least two sound guide rings are spaced apart, and the at least two sound guide rings are symmetrically arranged between at least two speakers; A middle partition is disposed between at least two of the sound guide rings, one end of the sound guide ring is connected to the loudspeaker, and the other end of the sound guide ring is spaced apart from the middle partition; The sound guide ring and the middle partition can form a guiding acoustic cavity to transmit the sound waves output by the loudspeaker.

[0008] According to this application, an omnidirectional modular wind tunnel standard sound source includes a sound-generating module. The sound-generating module includes at least two loudspeakers, at least two sound guide rings, and a middle partition. The at least two loudspeakers are arranged opposite each other and are symmetrical along the axial direction of the sound-generating module. The loudspeakers are used to output sound waves. The at least two sound guide rings are spaced apart and symmetrically arranged between the at least two loudspeakers. The middle partition is located in the middle of the at least two sound guide rings. One end of the sound guide ring is connected to the loudspeaker, and the other end of the sound guide ring is spaced apart from the middle partition. The sound guide rings and the middle partition can form a guiding acoustic cavity to transmit the sound waves output by the loudspeakers. In this way, by cooperating with at least two loudspeakers, at least two sound guide rings, and a middle partition, the sound wave propagation path is optimized, the reflection of sound waves inside the cavity of the omnidirectional modular wind tunnel standard sound source is reduced, the acoustic interference caused by reflection is effectively weakened, the sound energy consumption is reduced, the stable output of sound power is ensured, the sound output capability of the loudspeakers is improved, and the overall acoustic performance of the omnidirectional modular wind tunnel standard sound source is enhanced. It can also form at least two guiding sound cavities to guide the sound waves to be uniformly and stably distributed in the circumferential direction and polar direction (especially in the ±60° polar angle range) to achieve a good far-field omnidirectional sound field, ensuring that the omnidirectional modular wind tunnel standard sound source can generate an ideal spherical sound field within the measurement angle range.

[0009] Optionally, the sound guiding pressure ring includes a straight segment and an arc segment, the straight segment being connected to the arc segment, and the arc segment being closer to the middle partition than the straight segment; the middle partition includes at least two symmetrically arranged curved segments, the center of which protrudes from the outer edge along the axial direction of the sound-generating module; the arc segment and the curved segment are spaced apart to form the guiding sound cavity, and sound waves can enter the guiding sound cavity through the interior of the straight segment; the guiding sound cavity includes a guiding inlet and a guiding outlet; one end of the arc segment near the straight segment forms the guiding inlet with the center of the curved segment, and the other end of the arc segment is close to the outer edge of the curved segment to form the guiding outlet; the area of ​​the guiding inlet is smaller than the area of ​​the guiding outlet to form a gradually expanding and varying guiding sound cavity.

[0010] Optionally, the sound-generating module further includes a perforated plate that covers the guide outlet, and the guide acoustic cavity is capable of transmitting sound waves to the perforated plate.

[0011] Optionally, the sound-generating module further includes a damping plate, which is sleeved on the outside of the perforated plate. The perforated plate can transmit sound waves to the damping plate and propagate them outward through the damping plate.

[0012] Optionally, the sound-generating module further includes at least two connectors, which are spaced apart along the circumferential direction of the sound-generating module. The connectors combine and connect the sound guide rings and the middle partition, and the middle partition is fixed to the middle of the at least two sound guide rings by the connectors.

[0013] Optionally, the sound-generating module further includes at least two supports and a damping plate. The at least two supports are symmetrically arranged and disposed outside the at least two speakers. The connector can fix the speakers to the supports through the sound guide ring. The outer surface of the supports along the radial direction of the sound-generating module is flush with the outer surface of the damping plate along the radial direction of the sound-generating module, so that the outer surface of the sound-generating module is flush.

[0014] Optionally, the omnidirectional modular wind tunnel standard sound source further includes a housing module, which is connected to the sound-generating module. The housing module includes a front cover and a rear cover, which are respectively disposed at both ends of the sound-generating module along the axial direction of the sound-generating module. The outer contours of the front cover and the rear cover are both minimum drag rotating body structures or the cross-section along the axial direction of the sound-generating module is a laminar airfoil structure.

[0015] Optionally, the front cover has an inner cavity, the rear cover has an inner cavity, the inner cavities of the front cover and the rear cover are symmetrically arranged at both ends of the sound-generating module, and both the inner cavities of the front cover and the rear cover are either empty or filled with sound-absorbing material.

[0016] Optionally, the housing module further includes a tail support rod connected to the rear cover, the tail support rod being used to fix the omnidirectional modular wind tunnel standard sound source into the aeroacoustic wind tunnel.

[0017] Optionally, the omnidirectional modular wind tunnel standard sound source includes at least two sound-generating modules, and the at least two sound-generating modules are connected in series along the axial direction of the sound-generating modules. Attached Figure Description

[0018] The following figures are included as part of this application for understanding the application. The figures illustrate embodiments of the application and their descriptions, explaining the apparatus and principles of the application. In the figures, Figure 1 This is a three-dimensional schematic diagram of an omnidirectional modular wind tunnel standard sound source according to an embodiment of this application; Figure 2 for Figure 1 An exploded perspective view of the sound-generating module shown; Figure 3 for Figure 2 The diagram shows a cross-sectional view of the sound-generating module, omitting the perforated plate and damping plate. Figure 4 for Figure 1 A schematic cross-sectional view of a standard sound source for an omnidirectional modular wind tunnel is shown. Figure 5 This is a directivity pattern of the omnidirectional modular wind tunnel standard sound source in the embodiments of this application; Figure 6 This is a simulation result diagram of the omnidirectional modular wind tunnel standard sound source in the embodiments of this application.

[0019] Explanation of reference numerals in the attached figures: 1: Omnidirectional modular wind tunnel standard sound source; 10: Sound generation module; 11: Speaker; 111: First mounting hole; 112: Flange; 12: Sound guide ring; 121: Straight segment; 122: Curved segment; 123: Second mounting hole; 124: Third mounting hole; 13: Middle partition; 131: Curved surface segment; 132: Fourth mounting hole; 14: Guided acoustic cavity; 141: Guiding entrance; 142: Guiding exit; 15: Perforated plate; 16: Damping plate; 17: Connectors; 171: First connector; 172: Second connector; 18: Support; 181: First step surface; 182: Second step surface; 183: Fifth mounting hole; 184: Sixth mounting hole; 20: Shell module; 21: Front cover; 211: The inner cavity of the front cover; 22: Rear cover body; 221: The inner cavity of the rear cover; 23: Tail support rod. Detailed Implementation

[0020] The following description provides numerous specific details to offer a more thorough understanding of this application. However, it will be apparent to those skilled in the art that this application can be practiced without one or more of these details. In other instances, certain technical features well-known in the art have not been described to avoid confusion with this application.

[0021] To fully understand this application, detailed portions will be set forth in the following description in order to illustrate it. Obviously, implementation of this application is not limited to the specific details familiar to those skilled in the art. Preferred embodiments of this application are described in detail below; however, other embodiments may exist besides these detailed descriptions, and should not be construed as being limited to the embodiments set forth herein. It should be understood that the terminology used herein is intended only to describe particular embodiments and is not intended to limit the scope of this application. The singular forms “a,” “an,” and “the” are also intended to include the plural forms unless the context clearly indicates otherwise. When the terms “comprising” and / or “including” are used in this specification, they indicate the presence of the stated features, integrals, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components, and / or combinations thereof. The terms “upper,” “lower,” “front,” “rear,” “left,” “right,” and similar expressions used in this application are for illustrative purposes only and are not intended to be limiting.

[0022] The ordinal numbers such as "first" and "second" used in this application are merely identifiers and have no other meaning, such as a specific order. In this application, unless otherwise expressly specified and limited, "above" or "below" a second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of a second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" of a second feature includes the first feature being directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0023] The specific embodiments of this application will be described in more detail below with reference to the accompanying drawings, which illustrate representative embodiments of this application and are not intended to limit this application.

[0024] like Figure 1 As shown, this application provides an omnidirectional modular wind tunnel standard sound source 1. The omnidirectional modular wind tunnel standard sound source 1 can form a uniform spherical sound field within the target range and achieve far-field omnidirectionality, so that the omnidirectional modular wind tunnel standard sound source 1 can be used for acoustic testing and research in an aeroacoustic wind tunnel.

[0025] The far field refers to the spatial region in a free sound field environment without reflection or interference, where the distance from the sound source is much larger than the geometric and wavelength dimensions of the sound source. That is, when the distance from the sound source reaches a certain level, the sound pressure in the sound field gradually decreases with increasing distance, and the directivity of the sound source's radiation tends to stabilize, allowing sound waves in this region to propagate stably in the form of spherical waves, providing a stable testing environment for acoustic measurements. Omnidirectionality means that within a certain frequency range, when the sound source radiates sound waves in all directions, including the circumferential and polar directions, the difference in sound pressure level in each direction does not exceed ±3dB, and the sound energy distribution is uniform. An omnidirectional sound field is an ideal spherical sound field, which can meet the requirements of wind tunnel acoustic measurements for standard sound sources, providing reliable support for aeroacoustic research.

[0026] The omnidirectional modular wind tunnel standard sound source 1 includes a sound-generating module 10, which outputs sound waves that propagate away from the sound-generating module 10. The outer wall of the sound-generating module 10 has a straight section structure, and the sound-generating module 10 is symmetrical along its axial direction. Exemplarily, in this embodiment, the outer wall of the sound-generating module 10 is approximately cylindrical. This embodiment does not limit the specific structure of the sound-generating module 10.

[0027] like Figure 2As shown, the sound-generating module 10 includes at least two speakers 11, both of which are located inside the sound-generating module 10. The at least two speakers 11 are spaced apart. The at least two speakers 11 are located at opposite ends of the sound-generating module 10. The central axis of each speaker 11 coincides with the central axis of the sound-generating module 10. The at least two speakers 11 are arranged opposite each other and are symmetrical along the axial direction of the sound-generating module 10. Preferably, the speakers 11 have identical structures and are made of the same material.

[0028] The loudspeaker 11 is used to output sound waves. Specifically, the loudspeaker 11 can convert electrical signals into sound waves that can be radiated outwards. The loudspeaker 11 has a diaphragm and a driving assembly inside. When the loudspeaker 11 receives an electrical signal, the driving assembly can convert electrical energy into mechanical energy to drive the diaphragm to vibrate reciprocally. Thus, the loudspeaker 11 can stably output sound waves through the reciprocating vibration of the diaphragm. The frequency of the diaphragm vibration corresponds to the frequency of the electrical signal. By adjusting the frequency of the input electrical signal, the vibration frequency of the diaphragm can be adjusted, thereby adjusting the pitch of the output sound wave. The amplitude of the diaphragm vibration corresponds to the amplitude of the electrical signal. By adjusting the amplitude of the input electrical signal, the vibration amplitude of the diaphragm can be adjusted, thereby adjusting the sound pressure level of the output sound wave. Therefore, the sound pressure level of the sound wave output by the loudspeaker 11 can be adjusted, providing support for the sound-generating module 10 to output sound waves with a certain sound pressure level.

[0029] The diaphragms inside at least two loudspeakers 11 can vibrate synchronously. At least two sound waves output by each of the at least two loudspeakers 11 can propagate inside the sound-generating module 10. The at least two sound waves can propagate in a direction closer to each other within the sound-generating module 10. Thus, the at least two loudspeakers 11 are symmetrically arranged facing each other, and the sound waves output by the at least two loudspeakers 11 can superimpose, reducing the rate of energy attenuation during sound wave propagation. This allows the omnidirectional modular wind tunnel standard sound source 1 to possess a certain sound intensity; it also ensures that the sound waves have good directivity in the circumferential and polar directions (especially within the ±60° polar angle range), guaranteeing that the sound waves can propagate outwards uniformly and stably. Therefore, the omnidirectional modular wind tunnel standard sound source 1 can achieve a good far-field omnidirectional sound field in both the circumferential and polar directions.

[0030] The sound-generating module 10 also includes at least two sound guide rings 12, which are spaced apart. The at least two sound guide rings 12 are coaxially arranged. The at least two sound guide rings 12 are symmetrically arranged between at least two speakers 11. The central axis of the sound guide rings 12 coincides with the central axis of the speakers 11. Preferably, the sound guide rings 12 have the same structure and are made of the same material.

[0031] The sound guide ring 12 is generally hollow. It is positioned on one side of the speaker 11 along the axial direction of the sound-generating module 10. The sound guide ring 12 is connected to the speaker 11. The sound waves output by the speaker 11 can propagate inside the sound guide ring 12. In this way, the sound guide ring 12 provides a propagation path for the sound waves, effectively reducing scattering and reflection caused by spatial irregularities during propagation, reducing energy loss, and ensuring stable propagation of the sound waves along a specific direction.

[0032] The sound-generating module 10 also includes a middle partition 13, which is spaced apart from the sound-conducting pressure ring 12. The central axis of the middle partition 13 coincides with the central axis of the sound-conducting pressure ring 12. The middle partition 13 is located between at least two sound-conducting pressure rings 12. The middle partition 13 is located at the center of the sound-generating module 10 along the axial direction of the sound-generating module 10.

[0033] A sound guide ring 12 is located between the speaker 11 and the intermediate partition 13 along the axial direction of the sound-generating module 10. One end of the sound guide ring 12 is connected to the speaker 11, and the other end of the sound guide ring 12 is spaced apart from the intermediate partition 13. The sound guide ring 12 and the intermediate partition 13 can form a guide cavity 14 to transmit the sound waves output by the speaker 11. The speaker 11 can transmit sound waves to the guide cavity 14 through the sound guide ring 12. The end of the guide cavity 14 away from the speaker 11 is connected to the outside of the sound-generating module 10, and the sound waves in the guide cavity 14 can propagate towards the outside of the sound-generating module 10.

[0034] In this way, the guide cavity 14 optimizes the sound wave propagation path, avoiding the blockage of sound wave propagation by the speaker 11, the sound guide ring 12, and the intermediate partition 13 forming a closed structure. This allows the sound waves output by the speaker 11 to propagate to the outside of the sound generation module 10, ensuring the normal operation of the sound generation module 10. Furthermore, the guide cavity 14 can guide the direction of sound wave propagation, effectively reducing the energy consumption caused by multiple reflections of sound waves within the guide cavity 14. This makes the diaphragm vibration of the speaker 11 more stable, improves the sound generation capability of the speaker 11, increases the radiation efficiency of the speaker 11, ensures stable output of sound power, and enhances the acoustic performance of the omnidirectional modular wind tunnel standard sound source 1.

[0035] At least two sound-guiding pressure rings 12 are symmetrically arranged at both ends of the intermediate partition 13, such that at least two guiding acoustic cavities 14 are symmetrically arranged at both ends of the intermediate partition 13. Preferably, the at least two guiding acoustic cavities 14 have the same structure. The sound waves output by the at least two guiding acoustic cavities 14 can be superimposed on each other. In this way, the at least two loudspeakers 11 are at the same distance from the intermediate partition 13, and the at least two guiding acoustic cavities 14 are symmetrical, so that the at least two loudspeakers 11 arranged symmetrically facing each other can achieve a directional sound field with good symmetry in the circumferential and polar directions after being given the same excitation. It can also effectively avoid the influence of the sound pressure generated by the at least two loudspeakers 11 under high sound intensity conditions on each other's diaphragms. In addition, the at least two guiding acoustic cavities 14 guide the sound waves to be uniformly and stably distributed in the circumferential and polar directions (especially in the ±60° polar angle range) to achieve a good far-field omnidirectional sound field, ensuring that the omnidirectional modular wind tunnel standard sound source 1 can generate an ideal spherical sound field within the measurement angle range.

[0036] According to the present application, an omnidirectional modular wind tunnel standard sound source 1 includes a sound-generating module 10. The sound-generating module 10 includes at least two loudspeakers 11, at least two sound guide rings 12, and a middle partition 13. The at least two loudspeakers 11 are arranged opposite each other and are symmetrical along the axial direction of the sound-generating module 10. The loudspeakers 11 are used to output sound waves. The at least two sound guide rings 12 are spaced apart and symmetrically arranged between the at least two loudspeakers 11. The middle partition 13 is disposed in the middle of the at least two sound guide rings 12. One end of the sound guide ring 12 is connected to the loudspeaker 11, and the other end of the sound guide ring 12 is spaced apart from the middle partition 13. The sound guide rings 12 and the middle partition 13 can form a guiding acoustic cavity 14 to transmit the sound waves output by the loudspeakers 11. In this way, by cooperating with at least two loudspeakers 11, at least two sound guide rings 12, and a middle partition 13, the sound wave propagation path is optimized, the reflection of sound waves inside the cavity of the omnidirectional modular wind tunnel standard sound source 1 is reduced, the acoustic interference caused by reflection is effectively weakened, the sound energy consumption is reduced, the stable output of sound power is ensured, the sound production capability of loudspeakers 11 is improved, and the overall acoustic performance of the omnidirectional modular wind tunnel standard sound source 1 is enhanced. It can also form at least two guide cavities 14 to guide the sound waves to be uniformly and stably distributed in the circumferential direction and polar direction (especially in the ±60° polar angle range) to achieve a good far-field omnidirectional sound field, ensuring that the omnidirectional modular wind tunnel standard sound source 1 can generate an ideal spherical sound field within the measurement angle range.

[0037] like Figure 3As shown, the sound guiding pressure ring 12 includes a straight segment 121 and an arc segment 122, which are located on the inner wall of the sound guiding pressure ring 12 along the radial direction of the sound generating module 10. The straight segment 121 and the arc segment 122 are arranged adjacent to each other along the axial direction of the sound generating module 10. The straight segment 121 and the arc segment 122 are connected, and the arc segment 122 is closer to the middle partition 13 than the straight segment 121. Preferably, the straight segment 121 and the arc segment 122 are integrally formed.

[0038] The channel inside the straight segment 121 is connected to the channel inside the curved segment 122. The straight segment 121 is closer to the speaker 11 than the curved segment 122. The sound waves output by the speaker 11 can propagate into the straight segment 121. The sound waves can propagate from the inside of the straight segment 121 to the inside of the curved segment 122.

[0039] A portion of the intermediate partition 13 is located inside the arc segment 122. The intermediate partition 13 includes at least two symmetrically arranged curved segments 131, the central axes of which coincide. The at least two curved segments 131 are symmetrically arranged on both sides of the intermediate partition 13 along the axial direction of the sound-generating module 10. The center of each curved segment 131 protrudes beyond its outer edge along the axial direction of the sound-generating module 10. The curved segments 131 are generally curved structures. Preferably, the curved segments 131 have the same structure as each other.

[0040] The curved segment 122 and the curved surface segment 131 are spaced apart to form a guide cavity 14. Sound waves can enter the guide cavity 14 through the interior of the straight segment 121. Preferably, the center of the curved surface segment 131 corresponds to the end of the curved segment 122 closest to the straight segment 121, and the edge of the curved surface segment 131 corresponds to the end of the curved segment 122 furthest from the straight segment 121, and the inner wall of the guide cavity 14 is smooth. In this way, the curved segment 122 of the sound guide ring 12 and the curved surface segment 131 of the intermediate partition 13 are arranged opposite each other so that sound waves in the straight segment 121 can directly enter the guide cavity 14, and the guide cavity 14 can also guide the sound waves to propagate to the outside of the sound-generating module 10.

[0041] The guiding acoustic cavity 14 includes a guiding inlet 141 and a guiding outlet 142, which are located at opposite ends of the guiding acoustic cavity 14. One end of the arc segment 122, near the straight segment 121, forms the guiding inlet 141 with the center of the curved surface segment 131. The other end of the arc segment 122 approaches the outer edge of the curved surface segment 131 to form the guiding outlet 142. Both the curved surface segment 131 and the arc segment 122 are curved structures, and both have a certain curvature. The curvature of the arc segment 122 is different from that of the curved surface segment 131. This application embodiment does not limit the curvature of either the curved surface segment 131 or the arc segment 122.

[0042] The guide inlet 141 opens towards the speaker 11, allowing sound waves output from the speaker 11 to enter the guide cavity 14 through the guide inlet 141. The guide outlet 142 opens towards the outside of the sound-generating module 10, allowing sound waves within the guide cavity 14 to propagate to the outside of the sound-generating module 10 through the guide outlet 142. The area of ​​the guide inlet 141 is smaller than the area of ​​the guide outlet 142, forming a gradually expanding guide cavity 14.

[0043] For example, the radius of line segment 121 is The radius of the guide entrance 141 is equivalent to... The maximum diameter of the middle partition 13 is This is equivalent to the radius of guide outlet 142 being The distance between the other end of the arc segment 122 and the outer edge of the curved surface segment 131 along the axial direction of the sound-generating module 10 is t, which is equivalent to the length of the guide outlet 142 along the axial direction of the sound-generating module 10 being t.

[0044] According to the theory of acoustic waveguides, for an acoustic waveguide (a rigid, circular straight tube) with radius r, there exists a fixed cutoff frequency. The formula for calculating the cutoff frequency when a sound wave propagates in a sound waveguide is: .in, The speed of sound is 343 m / s. When the frequency of the sound wave is below the cutoff frequency... At this time, only plane waves (the lowest order mode of sound waves) are allowed to propagate continuously inside the acoustic waveguide, while the propagation of higher order mode waves is suppressed, causing the higher order mode waves of sound waves to attenuate rapidly inside the tube.

[0045] Preferably, the sound guide ring 12 is a circular rigid straight tube. Since the radius of the arc segment 122 is not less than the radius of the straight segment 121, the sound guide ring 12 can be adjusted by changing its radius. It effectively suppresses the propagation of higher-order modes in sound waves, ensures the purity of the sound source at low frequencies, and enables sound waves to propagate uniformly and stably in the circumferential and polar directions (especially in the ±60° polar angle range).

[0046] Furthermore, the radius of the straight segment 121 is the same as the radius of one end of the arc segment 122, and the radius of the other end of the arc segment 122 is the same as the radius of the intermediate partition 13. The area at the guide inlet 141 is the same as the cross-sectional area of ​​the straight segment 121, and the cross-section of the straight segment 121 is circular. Therefore, the area at the guide inlet 141 of the guide cavity 14 is... The guide outlet 142 is similar to the outer surface of a cylinder, and the area of ​​the guide outlet 142 of the guide cavity 14 is... By adjusting the value of t, it is possible to make This forms a gradually expanding guide cavity 14. By adjusting the curvature of the curved surface segment 131 and the arc segment 122, as well as their bending directions, a gradually expanding guide cavity 14 can be formed. In this way, the arc segment 122 and the curved surface segment 131 work together to form the gradually expanding guide cavity 14, guiding the propagation direction of sound waves, reducing sound wave reflection within the guide cavity 14, and lowering sound wave energy loss. This makes the diaphragm vibration of the loudspeaker 11 more stable, improving the loudspeaker 11's sound production capability, increasing the loudspeaker 11's radiation efficiency, ensuring stable output of sound power, and enhancing the overall acoustic performance of the omnidirectional modular wind tunnel standard sound source 1. It also ensures that sound waves are uniformly and stably distributed in the circumferential and polar directions (especially within the ±60° polar angle range) to achieve a good far-field omnidirectional sound field, ensuring that the omnidirectional modular wind tunnel standard sound source 1 can generate an ideal spherical sound field within the measurement angle range.

[0047] The sound-generating module 10 also includes a perforated plate 15, the central axis of which coincides with the central axis of the intermediate partition 13. The perforated plate 15 is sleeved on the outside of the sound-guiding pressure ring 12 and the intermediate partition 13 along the radial direction of the sound-generating module 10. The guiding acoustic cavity 14 formed by the intermediate partition 13 and the sound-guiding pressure ring 12 can transmit sound waves to the outside of the sound-generating module 10 through the perforated plate 15.

[0048] Furthermore, combined Figure 2 , Figure 3 and Figure 4 As shown, a perforated plate 15 is fitted over the guide outlet 142. The perforated plate 15 covers the guide outlet 142. The perforated plate 15 can be made of metal materials such as aluminum plate or stainless steel plate. This application embodiment does not limit the specific structure and material of the perforated plate 15.

[0049] The perforated plate 15 includes multiple through holes, all of which penetrate the perforated plate 15 along the radial direction of the sound-generating module 10. Preferably, the through holes have the same structure as each other. The multiple through holes are equidistantly arranged along the axial direction of the perforated plate 15. The multiple through holes are equidistantly arranged along the circumferential direction of the perforated plate 15. Optionally, the through holes can be circular holes, square holes, hexagonal holes, etc. The specific structure of the through holes is not limited in the embodiments of this application.

[0050] Sound waves can propagate from the guide cavity 14 towards the perforated plate 15, allowing the guide cavity 14 to transmit sound waves to the perforated plate 15. Sound waves can also propagate outwards from the sound-generating module 10 through the through-holes in the perforated plate 15. Preferably, the perforated plate 15 has a high perforation rate. This high perforation rate allows the sound waves transmitted from the guide cavity 14 to pass smoothly through the perforated plate 15 and propagate outwards in a specific direction, reducing reflection loss and flow resistance, decreasing energy consumption, and improving propagation efficiency. This ensures effective outward radiation of sound waves; it also effectively prevents sound waves from concentrating in localized areas of the perforated plate 15 and avoids superposition with subsequently propagating sound waves to form standing waves, thus effectively ensuring uniform and stable propagation of sound waves.

[0051] The sound-generating module 10 also includes a damping plate 16, which is sleeved on the outside of the perforated plate 15, and the perforated plate 15 supports the damping plate 16. The axial lengths of the damping plate 16 and the perforated plate 15 can be equal, or the axial length of the damping plate 16 can be slightly greater than that of the perforated plate 15. The central axis of the damping plate 16 coincides with the central axis of the perforated plate 15. The damping plate 16 can fix the perforated plate 15 to the outside of the guide outlet 142. Optionally, the damping plate 16 is connected to the perforated plate 15. For example, the damping plate 16 can be fixed to the outside of the perforated plate 15 by adhesive bonding. The connection method between the damping plate 16 and the perforated plate 15 in this embodiment is not limited, as long as they can cooperate to propagate sound waves outward.

[0052] The damping plate 16 can be made of damping materials such as rubber, felt, or foam to shield external airflow and block internal cavities. Preferably, the damping plate 16 has a porous structure to allow sound waves to propagate through it. The porous structure of the damping plate 16 corresponds to the through holes of the perforated plate 15. In this way, the perforated plate 15 can transmit sound waves to the damping plate 16 and propagate outward through it. The damping plate 16 can also filter outwardly radiated sound waves; at the same time, it can also block the internal cavities of the sound-generating module 10, avoiding cavity noise and resonance problems caused by airflow, effectively reducing adverse effects such as sound energy loss, frequency distortion, and turbulence noise caused by flow effects, and improving the acoustic purity of the sound-generating module 10.

[0053] The sound-generating module 10 also includes at least two connectors 17, both of which are located inside the sound-generating module 10. The axial direction of the connectors 17 is parallel to the axial direction of the sound-generating module 10. The at least two connectors 17 are spaced apart along the circumferential direction of the sound-generating module 10. Preferably, the connectors 17 have the same structure. The at least two connectors 17 are equidistantly arranged along the circumferential direction of the sound-generating module 10. This application embodiment does not limit the number of connectors 17.

[0054] Connector 17 combines and connects the sound guide ring 12 and the intermediate partition 13. Exemplarily, the sound guide ring 12 has a second mounting hole 123 and a third mounting hole 124, and the intermediate partition 13 has a fourth mounting hole 132. The axial directions of the second mounting hole 123 and the fourth mounting hole 132 are parallel, and both are parallel to the axial direction of the connector 17. The central axes of the second mounting hole 123 and the fourth mounting hole 132 coincide, and both coincide with the central axis of the connector 17. Thus, the connector 17 can pass through the second mounting hole 123 and the fourth mounting hole 132 to connect the sound guide ring 12 and the intermediate partition 13 together.

[0055] Since the sound-generating module 10 has at least two connectors 17, the sound guide ring 12 has at least two corresponding second mounting holes 123. Preferably, the second mounting holes 123 are identical in construction. The at least two second mounting holes 123 are equidistantly arranged along the circumferential direction of the sound guide ring 12. The intermediate partition 13 has at least two corresponding fourth mounting holes 132. Each connector 17 has one corresponding second mounting hole 123 and a fourth mounting hole 132, which will not be described in detail here. In this way, the connectors 17 can fix the sound guide ring 12 and the intermediate partition 13 together, enhancing the stability of the overall structure.

[0056] Since the sound-generating module 10 includes at least two sound-guiding pressure rings 12 and a middle partition 13, the middle partition 13 is fixed to the middle of the at least two sound-guiding pressure rings 12 by a connector 17. As an optional embodiment, the same connector 17 can sequentially pass through at least two sound-guiding pressure rings 12 and the middle partition 13 along the axial direction of the sound-generating module 10, so that the at least two sound-guiding pressure rings 12 and the middle partition 13 are connected together. The connector 17 can be connected to the sound-guiding pressure rings 12 and the middle partition 13 by a threaded connection. This application embodiment does not limit the specific connection method between the connector 17, the sound-guiding pressure rings 12, and the middle partition 13.

[0057] In another optional implementation, at least two connectors 17 are arranged adjacent to each other along the axial direction of the sound-generating module 10. One connector 17 passes through one sound guide ring 12, and the other connector 17 passes through another sound guide ring 12. One end of one connector 17 and one end of the other connector 17 are connected together in the fourth mounting hole 132 of the intermediate partition 13. In this way, at least two connectors 17 can cooperate with each other to pass through the intermediate partition 13, so that at least two sound guide rings 12 and the intermediate partition 13 are connected together.

[0058] In embodiments of this application, the connector 17 includes a first connector 171 and a second connector 172, which are coaxially arranged. The axial direction of the first connector 171 is parallel to the axial direction of the second connector 172. The central axis of the first connector 171 coincides with the central axis of the second connector 172. The first connector 171 can pass through one sound guide ring 12, and the second connector 172 can pass through another sound guide ring 12. The first connector 171 and the second connector 172 are connected to pass through the intermediate partition 13.

[0059] Optionally, the first connector 171 and the second connector 172 can be connected together by a threaded connection. The first connector 171 can be a single-ended circular nut post. The second connector 172 can be an internally threaded cylindrical pin. In this way, the first connector 171 and the second connector 172 cooperate to connect at least two sound guide rings 12 and the intermediate partition 13 together. The embodiments of this application do not limit the connection method of the first connector 171 and the second connector 172.

[0060] During installation, the first connector 171 and the second connector 172 can be connected on both sides of the middle partition 13. Then, the first connector 171 is inserted into the second mounting hole 123 of one sound guide ring 12, and the second connector 172 is inserted into the second mounting hole 123 of the other sound guide ring 12, so that at least two sound guide rings 12 are connected to the middle partition 13. Since the first connector 171 and the second connector 172 are of the same length, the middle partition 13 can be fixed to the middle of the at least two sound guide rings 12. The at least two sound guide rings 12 are symmetrically arranged, ensuring that the middle partition 13 is always positioned in the middle of the at least two sound guide rings 12.

[0061] For example, connector 17 includes a first connector 171, a second connector 172, at least one third connector, and at least one fourth connector. The first connector 171 and the second connector 172 are connected to pass through the middle partition 13. The first connector 171 and the third connector are connected to pass through the same sound guide ring 12. The second connector 172 and the fourth connector are connected to pass through another sound guide ring 12, so that at least two sound guide rings 12 are connected to the middle partition 13. Thus, the first connector 171, the second connector 172, the third connector, and the fourth connector cooperate to connect at least two sound guide rings 12 to the middle partition 13. This application does not limit the specific structure of connector 17.

[0062] like Figure 2 , Figure 3As shown, the sound-generating module 10 also includes at least two supports 18, which are spaced apart. The central axis of the support 18 coincides with the central axis of the speaker 11. The at least two supports 18 are symmetrically arranged and disposed outside the at least two speakers 11. Preferably, the supports 18 have the same structure and are made of the same material. In this way, the middle partition 13 is located in the middle of the at least two supports 18 along the axial direction of the sound-generating module 10, so that the middle partition 13 is always in the middle of the sound-generating module 10 along the axial direction of the sound-generating module 10.

[0063] The connector 17 secures the speaker 11 to the support 18 via the sound guide ring 12. In this embodiment, the outer diameter of the speaker 11 is smaller than the inner diameter of the support 18. The speaker 11 can be inserted into the support 18. The outer diameter of the sound guide ring 12 is adapted to the inner diameter of the support 18. The outer diameter of the sound guide ring 12 is smaller than the inner diameter of the support 18 so that the sound guide ring 12 can be inserted into the support 18 and fit tightly against the support 18. The sound guide ring 12 can abut against the speaker 11, and the speaker 11 can abut against the support 18. Specifically, the speaker 11 includes a flange 112 and at least two first mounting holes 111, the flange 112 protruding outward along the radial direction of the speaker 11. At least two first mounting holes 111 are provided on the flange 112 along the circumferential direction of the speaker 11. Preferably, the at least two first mounting holes 111 have the same construction. At least two first mounting holes 111 are equidistantly arranged along the circumferential direction of the loudspeaker 11. The inner wall of the support 18 includes an abutment surface, one end of the flange 112 along the axial direction of the loudspeaker 11 can abut against the abutment surface of the support 18, and the other end of the flange 112 along the axial direction of the loudspeaker 11 can abut against the sound guide ring 12.

[0064] During installation, the speaker 11 is first brought into contact with the support 18 using the sound guide ring 12, and then the speaker 11 is pressed and fixed onto the support 18 using the connector 17. Specifically, the support 18 has a fifth mounting hole 183, and a first mounting hole 111 is located between the third mounting hole 124 and the fifth mounting hole 183. The fifth mounting hole 183 corresponds to the first mounting hole 111, and the first mounting hole 111 corresponds to the third mounting hole 124. The central axis of the fifth mounting hole 183 coincides with the central axis of the first mounting hole 111, and the central axis of the first mounting hole 111 coincides with the central axis of the third mounting hole 124. The connector 17 can pass through the third mounting hole 124 and the first mounting hole 111 and then be inserted into the fifth mounting hole 183. By rotating the connector 17, one end of the flange 112 along the axial direction of the speaker 11 can be tightly fitted with the abutment surface of the support 18, and the other end of the flange 112 along the axial direction of the speaker 11 can be tightly fitted with the sound guide ring 12. In this way, the connector 17, through the sound guide ring 12, can press and fix the speaker 11 to the support 18. The method of pressing the flange 112 with the sound guide ring 12 and fixing it with the connector 17 can prevent the speaker 11 from generating circumferential modes due to the circumferential non-uniformity of multiple fixed and unfixed points on the flange 112 when the speaker 11 vibrates and produces sound under high sound intensity conditions. This application does not limit the connection method of the support 18, speaker 11, sound guide ring 12, intermediate partition 13, and connector 17.

[0065] like Figure 2 As shown, the perforated plate 15, the damping plate 16, and at least two supports 18 are connected together. The central axis of the support 18 coincides with the central axis of the perforated plate 15 and the damping plate 16. Optionally, the support 18 is provided with at least two sixth mounting holes 184, which are spaced apart along the circumferential direction of the support 18. Preferably, the sixth mounting holes 184 have the same structure as each other. The at least two sixth mounting holes 184 are equidistantly arranged along the circumferential direction of the support 18.

[0066] The perforated plate 15 and the damping plate 16 can be connected to the support 18 through the sixth mounting hole 184. Optionally, the sixth mounting hole 184 can be an oblong hole, and the perforated plate 15 can be fixed to the support 18 with screws. In this way, the sixth mounting hole 184 can fix the perforated plate 15 and the damping plate 16 to the outside of the guide outlet 142; it can also play a positioning role during assembly, so that the perforated plate 15 and the damping plate 16 can be connected to one support 18 along one end of the sound-generating module 10, and to another support 18 along the other end of the sound-generating module 10. This application does not limit the connection method between the perforated plate 15, the damping plate 16 and the support 18.

[0067] In this way, the damping plate 16 can cover the outside of the guide cavity 14 through the perforated plate 15. The damping material can shield the inside (intermediate cavity) of the sound generating module 10, effectively protecting the inside of the sound generating module 10. It can also consume the kinetic energy of the airflow in the wind tunnel, effectively preventing the airflow in the wind tunnel from directly entering the inside of the sound generating module 10 and impacting the diaphragm of the speaker 11, reducing the influence of the airflow in the wind tunnel on the diaphragm of the speaker 11. It can also avoid cavity noise and resonance problems caused by the airflow passing through the inside of the sound generating module 10, ensuring that the diaphragms of at least two speakers 11 can maintain a stable vibration state in the wind tunnel airflow environment, and also ensuring the purity of the sound source output by at least two speakers 11.

[0068] The outer surface of the support 18 along the radial direction of the sound-generating module 10 is flush with the outer surface of the damping plate 16 along the radial direction of the sound-generating module 10, so that the outer surface of the sound-generating module 10 is flush. Specifically, the outer surface of the support 18 along the radial direction of the sound-generating module 10 includes a first step surface 181 and a second step surface 182, the diameter of the first step surface 181 being smaller than the diameter of the second step surface 182. The second step surface 182 protrudes from the first step surface 181 along the radial direction of the sound-generating module 10.

[0069] Both the damping plate 16 and the perforated plate 15 are fitted onto the outside of the first stepped surface 181. The perforated plate 15 is located between the first stepped surface 181 and the perforated plate 15 along the radial direction of the sound-generating module 10. The damping plate 16 is fitted onto the outside of the first stepped surface 181 through the perforated plate 15, so that the second stepped surface 182 is flush with the outer surface of the damping plate 16 along the radial direction of the sound-generating module 10. At the same time, the height difference between the first stepped surface 181 and the second stepped surface 182 can form a second abutment surface, and the damping plate 16 can abut against the second abutment surface, so that the outer surface of the sound-generating module 10 is flush. In this way, the damping plate 16 cooperates with at least two supports 18 to make the outer surface of the sound-generating module 10 flush, reducing the impact of airflow on the sound-generating module 10 in the wind tunnel, effectively suppressing the adverse effects of flow, ensuring the purity of the sound source, ensuring the stable output of sound power, improving the sound-generating capability of the loudspeaker 11, and enhancing the overall acoustic performance of the omnidirectional modular wind tunnel standard sound source 1.

[0070] like Figure 1 and Figure 4 As shown, the omnidirectional modular wind tunnel standard sound source 1 also includes a housing module 20, which is connected to the sound-generating module 10. The central axis of the housing module 20 coincides with the central axis of the sound-generating module 10.

[0071] The housing module 20 includes a front cover 21 and a rear cover 22, which are spaced apart. The front cover 21 and the rear cover 22 are arranged coaxially. The central axis of both the front cover 21 and the rear cover 22 coincides with the central axis of the sound-generating module 10. Optionally, both the front cover 21 and the rear cover 22 are made of rigid materials such as metal or resin to provide a certain structural strength.

[0072] The front cover 21 and the rear cover 22 are respectively disposed at both ends of the sound-generating module 10 along the axial direction. One end of the sound-generating module 10 along the axial direction is connected to the front cover 21, and the other end of the sound-generating module 10 along the axial direction is connected to the rear cover 22. Preferably, the surfaces of both the front cover 21 and the rear cover 22 can be polished to reduce wind resistance. In this way, the housing module 20 can fix the sound-generating module 10 through the front cover 21 and the rear cover 22, which enhances the overall structural strength and makes the omnidirectional modular wind tunnel standard sound source 1 have a streamlined shape without exposed bolts. This ensures the integrity of the aerodynamic shape of the omnidirectional modular wind tunnel standard sound source 1, disperses the impact force of airflow on the omnidirectional modular wind tunnel standard sound source 1, and effectively avoids the sound wave from being deflected due to reflection, scattering or blocking during propagation. This makes the sound wave uniformly and stably distributed in the circumferential direction and polar direction (especially in the ±60° polar angle range) to achieve a good far-field omnidirectional sound field. This ensures that the omnidirectional modular wind tunnel standard sound source 1 can generate an ideal spherical sound field within the measurement angle range.

[0073] The outer contours of the front cover 21 and the rear cover 22 are both minimum drag rotating bodies or laminar airfoil structures in cross-section along the axial direction of the sound-generating module 10. In this way, the front cover 21 and the rear cover 22 can minimize flow resistance, especially preventing flow separation or thick boundary layer flow near the sound source module in the center from affecting the sound source propagation characteristics.

[0074] Optionally, the cross-sections of both the front cover 21 and the rear cover 22 can be a portion of the NACA63(3)-018 laminar airfoil structure. In this embodiment, the drag coefficient is simplified and calculated with reference to the ESDU78019 document, given the length of the front cover 21 (the dimension along the axial direction of the sound-generating module 10), the length of the sound-generating module 10, and the length of the rear cover 22. The drag coefficient obtained by using a laminar airfoil structure is the smallest compared to other rotating body configurations such as von Karman Ogive, Lighthill Profile, Modified Ellipsoid, ESDU1&2, Tangent Ogive, Myring, and Power Law. Among them, the length directions of the front cover 21, the sound-generating module 10, and the rear cover 22 are all parallel to the axial direction of the sound-generating module 10. The specific calculation process of the drag coefficient in this embodiment is similar to the specific calculation process of the drag coefficient in the prior art, and will not be repeated here. The use of a laminar airfoil structure in the wind tunnel allows the airflow to flow smoothly near the omnidirectional modular wind tunnel standard sound source 1, effectively avoiding flow separation or thick boundary layer flow that would affect the sound wave propagation characteristics near the central omnidirectional modular wind tunnel standard sound source 1. This reduces the impact of airflow on the sound source propagation characteristics and ensures the omnidirectionality and stability of the omnidirectional modular wind tunnel standard sound source 1.

[0075] The front cover 21 has an inner cavity 211, and the rear cover 22 has an inner cavity 221. The central axis of the inner cavity 211 coincides with the central axis of the inner cavity 221. The inner cavities 211 and 221 are symmetrically arranged at both ends of the sound-generating module 10. Preferably, both the inner cavities 211 and 221 are streamlined structures. This symmetrical arrangement ensures that the back cavity spaces of at least two speakers 11 within the sound-generating module are symmetrical, reducing the influence of the front cover 21 and rear cover 22 on the sound field directivity of the sound-generating module 10 in the polar angular direction, and ensuring consistent sound output from the at least two speakers 11.

[0076] Optionally, both the inner cavity 211 of the front cover and the inner cavity 221 of the rear cover are either empty or filled with sound-absorbing material. In this way, the spatial states of the inner cavity 211 of the front cover and the inner cavity 221 of the rear cover are the same, so that the acoustic performance of the inner cavity 211 of the front cover and the inner cavity 221 of the rear cover are the same, thereby making the sound waves output from at least two guide cavities 14 correspond.

[0077] When both the inner cavity 211 and the inner cavity 221 of the front and rear covers are empty, the symmetrical cavity structure makes the sound wave propagation path completely symmetrical, so that the conditions for sound wave propagation in the inner cavity 211 and the inner cavity 221 of the rear cover are the same, reducing the directional deviation in the sound wave propagation process, and making the sound wave uniformly and stably distributed in the circumferential direction and polar direction (especially in the ±60° polar angle range), so as to achieve a good far-field omnidirectional sound field and ensure that the omnidirectional modular wind tunnel standard sound source 1 can generate an ideal spherical sound field within the measurement angle range.

[0078] When both the inner cavity 211 and the inner cavity 221 of the front and rear covers are filled with sound-absorbing material, the sound-absorbing material can absorb sound and reduce noise. This allows the sound-absorbing material in the two symmetrical cavities to absorb the noise generated during sound wave propagation, reduce sound wave reflection, weaken the impact of standing waves on the acoustic performance of the loudspeaker, improve the low-frequency performance of the loudspeaker, and ensure the purity of the sound source, so that both sound waves can change uniformly. It also makes the conditions for sound wave propagation in the inner cavity 211 and the inner cavity 221 of the front and rear covers the same, reduces the directivity deviation during sound wave propagation, and makes the sound waves uniformly and stably distributed in the circumferential direction and polar direction (especially in the ±60° polar angle range), so as to achieve a good far-field omnidirectional sound field and ensure that the omnidirectional modular wind tunnel standard sound source 1 can generate an ideal spherical sound field within the measurement angle range.

[0079] The housing module 20 also includes a tail support rod 23, which is connected to the rear cover 22. The central axis of the tail support rod 23 coincides with the central axis of the rear cover 22. Optionally, the tail support rod 23 can be connected to the rear cover 22 by a threaded connection. This embodiment does not limit the connection method between the tail support rod 23 and the rear cover 22.

[0080] The tail support rod 23 is used to fix the omnidirectional modular wind tunnel standard sound source 1 into the aeroacoustic wind tunnel. Adjusting the position of the tail support rod 23 according to actual needs allows the omnidirectional modular wind tunnel standard sound source 1 to be fixed in a specific position within the aeroacoustic wind tunnel to meet different experimental requirements. Optionally, the tail support rod 23 can be made of high-strength materials such as alloy steel. In this way, the tail support rod 23 can provide stable support for the omnidirectional modular wind tunnel standard sound source 1, effectively preventing it from swaying under the high-speed airflow of the wind tunnel, thus improving the stability and reliability of the omnidirectional modular wind tunnel standard sound source 1 structure.

[0081] The omnidirectional modular wind tunnel standard sound source 1 includes at least two sound-generating modules 10, with the central axes of the at least two sound-generating modules 10 coinciding. The at least two sound-generating modules 10 are arranged adjacent to each other along the axial direction of the sound-generating modules. Preferably, the sound-generating modules are identical in construction. The at least two sound-generating modules 10 are connected in series along the axial direction of the sound-generating modules 10.

[0082] For example, one support 18 of one sound-generating module 10 is connected to an adjacent support 18 of another sound-generating module 10, and another support 18 of one sound-generating module 10 is spaced apart from another support 18 of the other sound-generating module 10 along the axial direction of the sound-generating module 10. At least four speakers 11 within at least two sound-generating modules 10 are all capable of outputting sound waves, allowing the sound waves to propagate outwards through at least four guide cavities 14. In this way, the sound-generating modules 10 can achieve a more complex omnidirectional sound field.

[0083] To verify whether the omnidirectional modular wind tunnel standard sound source 1 of this application embodiment can simultaneously satisfy the far-field omnidirectionality in both the circumferential and polar directions, the omnidirectional modular wind tunnel standard sound source 1 of this application embodiment was tested. Electroacoustic lumped parameter modeling of the loudspeaker 11 was performed using COMSOL, and the far-field radiated sound field was simulated. By changing the frequency of the sound wave output by the loudspeaker 11 and measuring the sound field, the experimental effect diagram of the omnidirectional modular wind tunnel standard sound source 1 can be obtained.

[0084] Figure 5 A directivity diagram of the omnidirectional modular wind tunnel standard sound source 1 is shown. Specifically, Figure 5 This graph shows the sound pressure level results at different sound wave frequencies (500Hz-6300Hz), within a polar angle range of ±90 degrees at a distance of 1m from the center of the standard sound source 1 in the omnidirectional modular wind tunnel. The coordinates inside the graph represent the total sound pressure level of the sound field, in dB; a larger radius indicates a higher total sound pressure level at that location. The numbers outside the graph represent the polar angle of the sound field. Different colored lines indicate the experimental effect of the sound field generated by sound waves of different frequencies in the polar angle direction. The sound waves are uniformly and stably distributed in the polar angle direction (especially within the ±60° polar angle range), achieving a good far-field omnidirectional sound field.

[0085] Figure 6 A simulation result diagram of the omnidirectional modular wind tunnel standard sound source 1 is shown. Specifically, Figure 6 This is a two-dimensional axisymmetric planar result of the sound field distribution cloud map around the standard sound source 1 of the omnidirectional modular wind tunnel when the frequency of the sound wave is 2000Hz, with the central axis of the sound source as the rotation axis. The horizontal and vertical axes are distances in meters; the colors in the figure represent sound pressure in Pa, with darker colors indicating higher sound pressure.

[0086] The results show that, for the circumferential direction, the omnidirectional nature of the omnidirectional modular wind tunnel standard sound source 1 is evident due to the completely symmetrical and uniform sound-generating structure. In the polar angle direction, the simulation results show that the consistency of the spherical sound field of the omnidirectional modular wind tunnel standard sound source 1 is also good, with directivity deviations all within 3dB, especially within the ±60° polar angle range, where the directivity deviation is very small, thus well meeting the design requirements. Therefore, through the shape design and the composite acoustic layering design of the sound-generating unit surface, the omnidirectional modular wind tunnel standard sound source 1 of this application embodiment can effectively avoid cavity noise and acoustic resonance, maintain stable flow conditions, and achieve far-field directivity close to the ideal point source propagation and radiation characteristics under flow conditions.

[0087] The omnidirectional modular wind tunnel standard sound source 1 of this application includes a sound-generating module 10 and a housing module 20. The sound-generating module 10 includes at least two supports 18, at least two loudspeakers 11, at least two sound guide rings 12, a middle partition 13, and a connector 17. The at least two supports 18, at least two loudspeakers 11, at least two sound guide rings 12, and middle partition 13 are fixed together by the connector 17. The at least two supports 18 are symmetrically and spaced apart, the at least two loudspeakers 11 are symmetrically arranged between the at least two supports 18, the at least two sound guide rings 12 are symmetrically arranged between the at least two loudspeakers 11, and the middle partition 13 is fixed between the at least two sound guide rings 12. The at least two supports 18, at least two loudspeakers 11, at least two sound guide rings 12, and connector 17 are all symmetrical, such that the middle partition 13 is fixed in the middle of the sound-generating module 10.

[0088] The housing module 20 includes a front cover 21 and a rear cover 22. The front cover 21 has a front cover inner cavity 211, and the rear cover 22 has a rear cover inner cavity 221. The front cover inner cavity 211 and the rear cover inner cavity 221 are symmetrically arranged at both ends of the sound-generating module 10, so that the back cavity spaces of at least two speakers 11 in the sound-generating module are symmetrical, reducing the influence of the front cover 21 and the rear cover 22 on the sound field directivity of the sound-generating module 10 in the polar angle direction, and ensuring that the sound output state of at least two speakers 11 is consistent.

[0089] The sound guide ring 12 includes an arc segment 122, and the intermediate partition 13 includes a curved segment 131. The arc segment 122 and the curved segment 131 are spaced apart to form a gradually expanding and varying guide cavity 14. The sound-generating module 10 also includes a perforated plate 15 and a damping plate 16. The perforated plate 15 and the damping plate 16 cooperate to allow the sound waves output by the speaker 11 to be transmitted to the guide cavity 14 and then to the perforated plate 15. The perforated plate 15 can transmit the sound waves to the damping plate 16 and then propagate them outward through the damping plate 16. In this way, by cooperating with at least two loudspeakers 11, at least two sound guide rings 12, and a middle partition 13, the sound wave propagation path is optimized, the reflection of sound waves inside the cavity of the omnidirectional modular wind tunnel standard sound source 1 is reduced, the acoustic interference caused by reflection is effectively weakened, and the adverse effects of flow effects are significantly suppressed, sound energy consumption is reduced, the stable output of sound power is ensured, the sound production capability of loudspeakers 11 is improved, and the overall acoustic performance of the omnidirectional modular wind tunnel standard sound source 1 is enhanced. At the same time, by cooperating with perforated plates 15 and damping plates 16 to shield the cavity inside the sound-generating module 10, the adverse effects of flow effects can be significantly suppressed. It can also form at least two guiding sound cavities 14 to guide sound waves to a uniform and stable distribution in the circumferential direction and polar direction (especially in the ±60° polar angle range) to achieve a good far-field omnidirectional sound field, ensuring that the omnidirectional modular wind tunnel standard sound source 1 can generate an ideal spherical sound field within the measurement angle range.

[0090] Unless otherwise defined, the technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. The terminology used herein is for descriptive purposes only and is not intended to limit the scope of this application. Terms such as “part” or “component” appearing herein can refer to a single part or a combination of multiple parts. Terms such as “installation” or “installation” appearing herein can refer to one component being directly attached to another component or one component being attached to another component via an intermediary. A feature described in one embodiment herein may be applied, alone or in combination with other features, to another embodiment, unless that feature is not applicable in that other embodiment or is otherwise stated.

[0091] This application has been described through the above embodiments; however, it should be understood that the above embodiments are for illustrative purposes only and are not intended to limit this application to the described embodiments. Furthermore, those skilled in the art will understand that this application is not limited to the above embodiments, and many more variations and modifications can be made based on the teachings of this application, all of which fall within the scope of protection claimed in this application. The scope of protection of this application is defined by the appended claims and their equivalents.

Claims

1. A standard omnidirectional modular wind tunnel sound source, characterized in that, Includes a sound-generating module, the sound-generating module comprising: At least two loudspeakers are arranged opposite each other and are symmetrical about each other along the axial direction of the sound-generating module. The loudspeakers are used to output sound waves. At least two sound guide rings are provided, the at least two sound guide rings are spaced apart, and the at least two sound guide rings are symmetrically arranged between at least two speakers; A middle partition is disposed between at least two of the sound guide rings, one end of the sound guide ring is connected to the loudspeaker, and the other end of the sound guide ring is spaced apart from the middle partition; The sound guide ring and the middle partition can form a guiding acoustic cavity to transmit the sound waves output by the loudspeaker.

2. The omnidirectional modular wind tunnel standard sound source according to claim 1, characterized in that, The sound guide ring includes a straight segment and an arc segment, the straight segment is connected to the arc segment, and the arc segment is closer to the middle partition than the straight segment; The intermediate partition includes at least two symmetrically arranged curved segments. The center of each curved segment protrudes from the outer edge along the axial direction of the sound-generating module. The arc segment and the curved segment are spaced apart to form the guide cavity. Sound waves can enter the guide cavity through the interior of the straight segment. The guide cavity includes a guide inlet and a guide outlet. One end of the arc segment near the straight segment forms the guide inlet with the center of the curved segment. The other end of the arc segment is close to the outer edge of the curved segment to form the guide outlet. The area of ​​the guide inlet is smaller than the area of ​​the guide outlet, so as to form the guide acoustic cavity that gradually expands and changes.

3. The omnidirectional modular wind tunnel standard sound source according to claim 2, characterized in that, The sound-generating module also includes a perforated plate that covers the guide outlet, and the guide acoustic cavity can transmit sound waves to the perforated plate.

4. The omnidirectional modular wind tunnel standard sound source according to claim 3, characterized in that, The sound-generating module also includes a damping plate, which is sleeved on the outside of the perforated plate. The perforated plate can transmit sound waves to the damping plate and propagate them outward through the damping plate.

5. The omnidirectional modular wind tunnel standard sound source according to claim 1, characterized in that, The sound-generating module further includes at least two connectors, which are spaced apart along the circumferential direction of the sound-generating module. The connectors combine and connect the sound guide rings and the middle partition, and the middle partition is fixed to the middle of the at least two sound guide rings by the connectors.

6. The omnidirectional modular wind tunnel standard sound source according to claim 5, characterized in that, The sound-generating module further includes at least two supports and a damping plate. The at least two supports are symmetrically arranged and disposed outside the at least two speakers. The connector can fix the speakers to the supports through the sound guide ring. The outer surface of the supports along the radial direction of the sound-generating module is flush with the outer surface of the damping plate along the radial direction of the sound-generating module, so that the outer surface of the sound-generating module is flush.

7. The omnidirectional modular wind tunnel standard sound source according to claim 1, characterized in that, The omnidirectional modular wind tunnel standard sound source also includes a shell module, which is connected to the sound-generating module. The shell module includes a front cover and a rear cover, which are respectively disposed at both ends of the sound-generating module along the axial direction of the sound-generating module. The outer contours of the front cover and the rear cover are both minimum drag rotating body structures or laminar airfoil structures in cross-section along the axial direction of the sound-generating module.

8. The omnidirectional modular wind tunnel standard sound source according to claim 7, characterized in that, The front cover has an inner cavity, and the rear cover has an inner cavity. The inner cavities of the front cover and the rear cover are symmetrically arranged at both ends of the sound-generating module. Both the inner cavities of the front cover and the rear cover are either empty or filled with sound-absorbing material.

9. The omnidirectional modular wind tunnel standard sound source according to claim 7, characterized in that, The housing module also includes a tail support rod, which is connected to the rear cover and is used to fix the omnidirectional modular wind tunnel standard sound source into the aeroacoustic wind tunnel.

10. The omnidirectional modular wind tunnel standard sound source according to claim 1, characterized in that, The omnidirectional modular wind tunnel standard sound source includes at least two sound-generating modules, and the at least two sound-generating modules are connected in series along the axial direction of the sound-generating modules.

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