Resonant strong sound generation method, system and optimized design method thereof

Abstract

The present disclosure provides a method and system for resonant strong sound generation, including: generating a continuous compressed air flow; converting the compressed air flow into a high-pressure air jet pulse according to a control signal to form a basic sound source; passing the basic sound source into a resonant horn, and through the synchronous excitation of the structural resonance of the horn side wall and the resonance of the air in the horn cavity, generating a fixed-frequency modulation on the basic sound source, so that the sound wave energy is concentrated at the target frequency, generating a high-intensity simple harmonic sound wave, and making the wavefront strictly parallel to the horn outlet and pointing perpendicular to the horn outlet. The optimization design method of the resonant strong sound generation system provided by the present disclosure includes: optimizing the cross-sectional curve of the resonant horn and the acoustic resonant frequency of the horn, optimizing the frequency synchronization of the structural local oscillation of the resonant horn and the acoustic resonance, and / or optimizing the position and arrangement of the jet hole and the vent nozzle in the whistle generator. The present disclosure can make the frequency and energy of the generated sound waves more concentrated.

Description

Technical Field

[0001] The present disclosure belongs to the technical field of low-frequency loudspeakers, and in particular relates to a resonant loud sounding method, system and optimization method thereof. Background Art

[0002] Strong sound devices are used in various industries, such as ① an efficient airport fog elimination device (Zhao Yun et al., invention patent application, publication number: CN111151088A, disclosing an efficient airport fog elimination system and its defogging method), ② acoustic rain enhancement (Huang Ruijun, invention patent application, publication number: CN106613576A, disclosing a beam acoustic rain enhancement device), and ③ an airport bird repellent device (Xi Baoshu et al., invention patent application, publication number: CN109430237A, disclosing a bird repellent device using a shock wave generator). The current disadvantages of this type of strong sound device are: ① the sound wave waveform at the speaker outlet is messy, resulting in poor sound directionality and a large beam angle, which is not conducive to ensuring long-distance transmission of sound waves; and ② the energy conversion efficiency of the sound generated by the equipment is low. Summary of the Invention

[0003] The present disclosure aims to solve one of the above-mentioned problems.

[0004] To this end, the first embodiment of the present disclosure provides a method for producing strong resonance sound that can make the frequency and energy of sound waves more concentrated, including:

[0005] Produces a continuous flow of compressed air;

[0006] Converting the compressed air flow into high-pressure air jet pulses according to a control signal to form a basic sound source;

[0007] The basic sound source is introduced into the resonant horn, and through the synchronous excitation of the structural resonance of the horn side wall and the resonance of the air in the horn cavity, the basic sound source is modulated at a fixed frequency, so that the sound wave energy is concentrated at the target frequency, high-intensity simple harmonic sound waves are generated, and the wave surface is strictly parallel to the horn outlet and points perpendicular to the horn outlet.

[0008] The first embodiment of the present disclosure provides a method for producing strong resonance sound, which has the following characteristics and beneficial effects:

[0009] The resonant strong sounding method provided by the embodiment of the first aspect of the present disclosure modulates the sound waves emitted by the sound generator into concentrated strong sound waves through resonance and energy orientation based on the focusing and resonance theory of the Bezier curve of sound waves. The outlet waveform is approximately a simple harmonic wave, and the outlet sound power reaches the maximum value.

[0010] The second aspect of the present disclosure provides a resonant strong sounding system that can concentrate the frequency and energy of sound waves, including:

[0011] an air compressor for generating a continuous flow of compressed air;

[0012] a control unit, the control unit being configured to generate a control signal;

[0013] a whistle sounder connected to the air compressor and the control unit, and configured to convert the compressed air flow into high-pressure air jet pulses according to the control signal, thereby forming a basic sound source; and

[0014] A sound wave modulation enhancement device includes a resonant horn connected to the whistle generator, which is used to pass the basic sound source into the resonant horn. Through the synchronous excitation of the structural resonance of the horn side wall and the resonance of the air in the horn cavity, the basic sound source is modulated at a fixed frequency, so that the sound wave energy is concentrated at the target frequency, generating high-intensity simple harmonic sound waves, and making the wave front strictly parallel to the horn outlet and pointing perpendicular to the horn outlet.

[0015] The resonant strong sounding system provided by the second embodiment of the present disclosure has the following features and beneficial effects:

[0016] The resonant strong sounding system provided by the embodiment of the second aspect of the present disclosure has a simple sounding principle, adopts a pneumatic whistle sounding method, uses high-pressure modulated airflow to generate strong sound waves, and generates high-intensity sound waves through modulation of a resonant speaker. It has the characteristics of low required power and high energy conversion rate; strong sound directionality, simple harmonic sound wave waveform at the outlet; and a small sound wave beam angle at the outlet.

[0017] In some embodiments, the radial cross-sectional curve of the horn side wall adopts a Bezier curve.

[0018] In some embodiments, the radial cross-sectional curve of the horn side wall satisfies:

[0019]

[0020]

[0021]

[0022] Where J0(x) is the 0th-order Bessel function, x is the independent variable of the Bessel function, Γ(m+1) is the gamma function, and m is a natural number from 0 to +∞; F(x) is the height coordinate corresponding to the side wall of the speaker, λ is the nominal sound wave wavelength of the resonant speaker, and k0 is the nominal sound wave number of the resonant speaker.

[0023] In some embodiments, a horn reinforcement ring is provided at the horn outlet, and the radial cross-sectional shape of the horn reinforcement ring smoothly transitions with the curve of the horn side wall and smoothly turns outward.

[0024] In some embodiments, the whistle sounder includes a motor, a rotor driven by the motor, a stator located outside the rotor, and a cylinder arranged between the motor and the rotor. The air compressor is connected to the rotor through the cylinder. A plurality of jet holes are evenly distributed on the circumferential surface of the stator, and a plurality of vent holes are evenly distributed on the circumferential surface of the rotor. When the motor drives the movable rotor to rotate, the jet holes and the vent holes periodically overlap and separate to form the high-pressure air jet pulses.

[0025] In some embodiments, the control signal generated by the control unit includes the rotational speed of the motor.

[0026] One of the optimization design methods for the upper resonance strong sounding system provided in the third aspect of the present disclosure includes:

[0027] Based on acoustic principles, multiple resonant frequencies corresponding to the resonant speakers of different sizes are calculated so that the sound source frequency of the rotary flute sound generator can be adjusted to one of the resonant frequencies. The control unit then adjusts the sound source frequency of the rotary flute sound generator based on the collected sound signal of the resonant strong sounding system to be consistent with the resonant frequency that achieves the optimal sounding effect.

[0028] The second method for optimizing the design of the upper resonance strong sounding system provided in the third embodiment of the present disclosure includes:

[0029] By analyzing the local oscillation modal of the structure of the resonant horn, the local oscillation frequency and vibration mode of the structure of the resonant horn are adjusted by adjusting the wall thickness of the horn side wall, adding a horn reinforcement ring at the horn outlet and / or adding a horn cutout on the horn side wall, so that the local oscillation frequency of a certain main vibration mode is consistent with a certain resonant frequency of the resonant horn.

[0030] The third method for optimizing the design of the upper resonance strong sounding system provided in the third embodiment of the present disclosure includes:

[0031] Based on the requirement that the high-pressure air jet pulse generated by the whistle sounder excites the structural resonance vibration mode of the resonant speaker at the corresponding frequency, the positions and arrangements of the air jet holes and the vent holes in the whistle sounder are set. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 This is a schematic diagram of the overall structure of the resonant strong sound generation system provided in the embodiment of the second aspect of the present disclosure.

[0033] Figure 2 A and B are Figure 1 The cross-sectional schematic diagram and three-dimensional structural schematic diagram of the resonant horn and reinforcement ring in the resonant strong sound system are shown.

[0034] Figure 3 A is Figure 1 The diagram shows the structure of the whistle sounder in the resonant strong sounding system. BE are examples of different arrangements of vent holes and jet holes.

[0035] Figure 4 Schematic diagram of the total deformation distribution of a Bessel horn under a local oscillation mode.

[0036] Figure 5 This is an example of adjusting the local oscillator frequency and mode by setting slits for the Bessel horn and its reinforcement ring.

[0037] Reference numerals:

[0038] 100-air compressor;

[0039] 200-control unit, frequency conversion control box 210;

[0040] 300 - whistle generator, 310 - stator, 311 - jet hole, 312 - vent hole, 320 - rotor, motor 330, air intake pipe 340;

[0041] 400-sound wave modulation enhancement device, 410-resonance horn, 411-horn inlet, 412-horn outlet, 413-incision, 420-horn reinforcement ring, 430-horn bracket. DETAILED DESCRIPTION

[0042] In order to make the purpose, technical solutions and advantages of this application more clearly understood, this application is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not intended to limit this application.

[0043] On the contrary, this application covers any alternatives, modifications, equivalents, and solutions made within the spirit and scope of this application as defined by the claims. Furthermore, to facilitate a better understanding of this application, certain specific details are described in detail below in the detailed description of this application. Those skilled in the art will be able to fully understand this application without these details.

[0044] The first embodiment of the present disclosure provides a method for producing strong resonance sound, comprising:

[0045] Produces a continuous flow of compressed air;

[0046] According to the control signal, the compressed air flow is converted into high-pressure air jet pulses to form the basic sound source;

[0047] The basic sound source is introduced into the resonant horn, and the structural resonance of the horn side wall and the resonance of the air in the horn cavity are synchronously excited to produce a fixed-frequency modulation on the basic sound source, so that the sound wave energy is concentrated on the target frequency, generating high-intensity simple harmonic sound waves, and making the wave surface strictly parallel to the horn outlet and pointing perpendicular to the horn outlet.

[0048] The second embodiment of the present disclosure provides a resonant strong sound system, the overall layout of which is shown in Figure 1 ,include:

[0049] An air compressor 100 for generating a continuous flow of compressed air;

[0050] A control unit 200 is configured to generate a control signal;

[0051] A whistle sounder 300 connected to the air compressor 100 and the control unit 200, configured to convert the compressed air flow into high-pressure air jet pulses according to a control signal, thereby forming a basic sound source; and

[0052] The sound wave modulation enhancement device 400 includes a resonant horn 410 connected to the whistle generator 300. It is used to pass a basic sound source into the resonant horn 410. Through the synchronous excitation of the structural resonance of the horn side walls and the resonance of the air in the horn cavity, the basic sound source is modulated at a fixed frequency, so that the sound wave energy is concentrated at the target frequency, generating high-intensity simple harmonic sound waves, and making the wave front strictly parallel to the horn outlet and pointing perpendicular to the horn outlet.

[0053] In some embodiments, see Figure 2 The sound wave modulation enhancement device 400 includes a resonant horn 410, which includes a sidewall, and a horn inlet 411 and a horn outlet 412 disposed at either end of the sidewall. The horn inlet 411 is securely connected to the air outlet of the whistle sound generator 300. Based on the theory of intracavity acoustic wave resonance of a horn using a Bessel curve as the cross-sectional shape of the sidewall, a curved horn sidewall surface suitable for resonance of sound waves at the target frequency is designed. The horn is then machined from metal into a solid horn body. During operation, the pulse waves emitted by the whistle sound generator 2 are modulated into high-intensity simple harmonic sound waves through resonance of the atmosphere within the horn cavity.

[0054] In some embodiments, the radial cross-sectional curve of the sidewall of the resonant horn 410 satisfies the following formula:

[0055]

[0056]

[0057]

[0058] in:

[0059] In formula (1), J0(x) is the zero-order Bessel function, x is the independent variable of the Bessel function; Γ(m+1) is the gamma function, m is a natural number from 0 to +∞;

[0060] In formula (2), F(x) is the height coordinate corresponding to the side wall of the resonant horn; λ is the nominal sound wave wavelength of the resonant horn, and its relationship with the sound velocity C and the nominal frequency f is λ = C / f; k0 is the nominal sound wave number of the resonant horn, k0 = 2πf / C = 2π / λ;

[0061] In formula (3), R(x) is the radial coordinate corresponding to the side wall of the resonant horn.

[0062] In one embodiment, taking into account the change in the direction of the Bessel function curve, the value range of x is 1 to 2.4; the nominal frequency is f = 87 Hz, and the speed of sound is C = 340 m / s; according to the above formula, the diameter of the resonant horn outlet corresponding to the nominal frequency of 87 Hz is 2988 mm, and the main body height is 1906 mm.

[0063] In some embodiments, to enhance the strength and durability of the resonant horn 410 and facilitate transportation and installation, a horn reinforcement ring 420 is provided at the horn outlet 412 of the resonant horn 410. This horn reinforcement ring 420 is a circular metal reinforcement structure. The radial cross-section of the horn reinforcement ring 420 should smoothly transition with the curve of the resonant horn 410 and smoothly turn outward to avoid sound wave scattering at the edge of the horn outlet 412 of the resonant horn 410. Optionally, the horn reinforcement ring 420 and the resonant horn 410 can be welded together to form an integral structure. The integral structure can also be mounted on a horn bracket 430 in a multi-point simply supported manner via the horn reinforcement ring 420. A platform for holding the whistle sounder 300 is provided in the center of the bottom of the horn bracket 430, and has functions such as height and level adjustment.

[0064] In some embodiments, see Figure 1 and Figure 3 In the middle A~E, the whistle sounder 300 is based on fluid mechanics and acoustic theory, using high-pressure air jet pulses to generate a strong sound source as the basic sound source of this system. Figure 1 and Figure 3In Figure A, the whistle sounder 300 includes a motor 330, a rotor 320 driven by the motor 330, a stator 310 located outside the rotor 320, a cylinder 350, a drive shaft 360, an air intake duct 340 connected to the rotor 320, and a bracket 370 supporting the entire whistle sounder. All are precision-machined from metal, and both the stator 310 and rotor 320 are hollow structures. To coordinate with the resonant horn 410, the motor 330 is typically positioned at the lower end of the whistle sounder 300, aligned with the air intake of the whistle sounder 300 and located outside the horn inlet 411 of the resonant horn 410 to avoid affecting the resonant horn cavity. The cylinder 350 is positioned between the rotor 320 and the motor 330. The air compressor 100 communicates with the rotor 320 via the air intake duct 340 and the cylinder 350, generating a continuous flow of compressed air into the rotor 320. Several jet holes 311 are evenly distributed around the circumference of the stator 310, and several vent holes 321 are evenly distributed around the circumference of the rotor 320. The motor 330 drives the rotor 320 via the drive shaft 360, causing the jet holes 311 and vent holes 321 to periodically overlap and separate, generating high-pressure air jet pulses. To ensure the precision of the whistle sounder 300 and improve energy efficiency, the rotor 320 is positioned within the stator 310. Contact ball bearings are used at each end of the rotor 320 and stator 310 to ensure stability and concentricity between the rotor 320 and stator 310. The spacing between the rotor 320 and stator 310 near the vent holes 321 and jet holes 311 is kept to less than 0.1 mm. During operation, the motor 330 drives the rotor 320 to rotate, and the compressed air supplied by the air compressor 100 enters the rotor 320 through the air inlet of the whistle sounder 300 and the opening at the bottom of the rotor 320. The large pressure regulating space inside the rotor 320 can keep the air pressure basically stable. As the rotor 320 rotates, the compressed air in the rotor 320 generates an outward high-pressure air jet pulse in the process of the air vents 321 on the side wall of the rotor 320 and the air injection holes 311 on the side wall of the stator 310 changing from non-overlapping to partial overlap, to complete overlap, to partial overlap, and finally to non-overlapping. This impacts the air in the cavity of the resonant speaker 410 and the side wall of the speaker, forming a pulsed sound wave. As the rotor 320 continues to rotate, the pulsed sound wave generated by the high-pressure air jet pulse is repeated continuously. After being modulated by the resonant speaker 410, it forms a high-intensity simple harmonic sound wave, which is emitted outward with the wavefront parallel to the speaker outlet 412. Figure 3 B and C are examples of providing 1 row and 12 columns of injection holes 311 and vent holes 321 on the side walls of the stator 310 and the rotor 320 respectively; see Figure 3 D and E in the middle are examples of providing two rows and four columns of injection holes 311 and ventilation holes 321 on the side walls of the stator 310 and the rotor 320, respectively.

[0065] In some embodiments, see Figure 1 The control unit 200 is the main control device of the sound system disclosed herein. Its function is to set and adjust the rotation speed of the motor 330 so that the sound wave frequency of the sound system meets the design requirements and reaches the optimal operating frequency. The control unit 200 includes a frequency conversion control box 210, which generally uses frequency conversion speed regulation and other methods to control the rotation speed of the motor 330. It initially works at the motor speed calculated based on the nominal frequency of the designed sound wave, the arrangement of the jet hole 311 and the vent hole 321; and by collecting the sound wave signal emitted by the sound system, through indicators such as sound pressure level and quality factor (Q factor), the rotation speed of the motor 330 is fine-tuned through a feedback adjustment algorithm so that the sound system disclosed herein reaches the optimal operating frequency. Optionally, at startup, the motor 330 can be gradually accelerated to the normal operating speed to reduce the mechanical impact of the equipment; when it is detected that the motor 330 is stuck or the rotation speed does not meet the standard, an alarm is issued or the air supply is cut off to ensure the safety of the sound system.

[0066] In some embodiments, the operation mode of the resonant strong sound system provided by the present disclosure is:

[0067] The air compressor 100 generates a continuous flow of compressed air, which is introduced into the whistle sounder 300 via the air intake duct 340. The whistle sounder 300 is powered by a diesel generator or a power source, which operates the motor 330. The frequency converter 210 adjusts the rotation speed of the rotor 320, thereby controlling the frequency of the primary sound source through the opening frequency of the air jet holes 311. The compressed air introduced by the air compressor 100 enters the rotor 320, and through the periodically open air jet holes 311, a pulsed compressed air jet of a certain frequency is generated. This pulsed compressed air jet impacts the side walls of the resonant horn 410, forming the primary sound source. The jet impacts the resonant horn 410, and the structural resonance of the horn side walls and the synchronous resonance of the air in the horn cavity are excited, resulting in a strong fixed-frequency modulation effect. This concentrates the sound wave energy at the target frequency, generating high-intensity simple harmonic sound waves, with the wavefront strictly parallel to and pointing perpendicular to the horn outlet.

[0068] The third aspect of the present disclosure provides an optimization design method for the resonant high-intensity sound-generating system. Based on mechanical and acoustic principles, three methods are provided for optimizing the sound effects at different physical stages during the generation of high-intensity simple harmonic sound waves by the resonant sound-generating system. While all three methods should generally be employed to optimize the system's sound effects and efficiency, one or more of these methods may be used.

[0069] Optimization method 1: Based on acoustic principles, multiple resonant frequencies corresponding to harmonic speakers of different sizes are calculated. According to the acoustic wave equation and the basic property that the radial energy of the internal sound wave of the resonant speaker is 0, the calculation formula (4) (5) of the resonant frequency of the resonant speaker is obtained, which is used to calculate multiple resonant frequencies corresponding to resonant speakers of different sizes:

[0070]

[0071]

[0072] Where J1(·) is the first-order Bessel function, L is the main height of the resonant horn, and the wave number k corresponding to the value of f when F(k) = 0 is res This is the resonant frequency of the resonant speaker.

[0073] For the resonant speaker with a nominal frequency of 87 Hz in this embodiment, its first two resonant frequencies can be determined to be 54.2 Hz and 96.3 Hz, respectively. Theoretically, at these resonant frequencies, the sound system of the present disclosure can achieve optimal sound effects. Therefore, according to optimization method 1, the sound source frequency of the whistle sounder 300 can be adjusted to one of the resonant frequencies, such as 54.2 Hz. Based on the collected sound signal, the frequency conversion control box 210 can then fine-tune the fundamental sound source frequency of the whistle sounder 300 to highly align with the resonant frequency that achieves optimal sound effects. This achieves the resonant effect of the resonant speaker and produces high-intensity simple harmonic sound waves emitted from the speaker outlet 412.

[0074] Optimization method 2 calculates the local oscillation modes and corresponding local oscillation frequency combination sequence of the overall structure consisting of the resonant horn 410 and the horn reinforcement ring 420 (hereinafter referred to as the "overall structure") through structural local oscillation analysis of the resonant horn. The overall structure is then optimized to adjust the local oscillation frequencies and modes so that the local oscillation frequency of one group is consistent with the resonant frequency of the resonant horn 410 and the corresponding local oscillation mode is coordinated with the arrangement of the air jet holes 311 of the whistle sounder 300.

[0075] Structural local oscillation analysis generally uses the damped modal analysis control equation:

[0076]

[0077] Among them, [M] represents the mass matrix of the overall structure, [C] is the damping matrix of the overall structure, and [K] is the stiffness matrix of the overall structure. is the acceleration vector of the entire structure, is the velocity vector of the entire structure, and {u} is the displacement vector of the entire structure. The overall damping matrix is constructed by combining the mass matrix and the stiffness matrix in proportion. In engineering analysis, the Rayleigh damping matrix is often used, namely:

[0078] [C]=α[M]+β[K]

[0079] Among them, α is a coefficient proportional to mass; β is a coefficient proportional to stiffness, with s -1and s. α and β are two undetermined constants that can be determined using the structural damping ratio obtained from actual measurements (actual measurements can directly give the modal damping ratio of the structure), or by given values of two modal damping ratios. Therefore, the formula [C] = α[M] + β[K] is converted into a form expressed in terms of damping ratios.

[0080] The vibration mode of the structure is orthogonal to the mass matrix and the stiffness matrix. Therefore, the linear combination of the mass matrix and the stiffness matrix must satisfy the orthogonal condition. Therefore, Rayleigh damping is a kind of orthogonal damping, and the expression is as follows:

[0081] C n =αM n +βK n

[0082] Among them, C n 、M n and K n are the n-th order Rayleigh damping matrix, mass matrix and stiffness matrix respectively;

[0083] Multiply the equation [C]=α[M]+β[K] by the transpose of the vibration mode and right multiplied vibration mode get:

[0084]

[0085]

[0086]

[0087] Because C n =2ξ n ω n M n , ω n is the natural angular frequency, so it satisfies:

[0088]

[0089] If any two modal damping ratios ξ are given, since the natural frequency is known, we can substitute them into the above formula to obtain two linear algebraic equations about the coefficients α and β, which can be solved to get the sum. Then the Rayleigh damping is determined. Assuming that the modal damping ratio ξ is given i and ξ j ,ω i and ω j are the i-th and j-th order natural angular frequencies respectively, and the matrix form of the sum can be written as:

[0090]

[0091] When the modal damping ratio ξ=ξi =ξ j When , the following formula is satisfied:

[0092]

[0093] Structural local oscillation analysis generally uses various structural numerical models and software solutions based on the above principles to obtain a series of local oscillation frequencies and corresponding modes.

[0094] The second optimization method uses a lower-order mode with circumferential symmetry, for example Figure 4 As shown, the speaker reinforcement ring is adjusted, the wall thickness of the resonant speaker side wall is adjusted, and a speaker cutout is added (for example, Figure 5 , that is, by cutting a number of radially arranged cuts 413 at equal intervals and lengths in the circumferential direction of the side wall of the resonant horn, etc., the local oscillation frequency and vibration mode of the overall structure composed of the resonant horn 410 and the horn reinforcement ring 420 in the selected mode are adjusted so that the local oscillation frequency is consistent with the selected resonant frequency of the resonant horn 410, thereby strengthening the resonance of the overall structure composed of the resonant horn 410 and the horn reinforcement ring 420 and the synchronous excitation of the resonance of the air in the horn cavity, so that the output sound intensity of the resonant sound system is significantly improved.

[0095] In some embodiments, by setting a certain shape of the speaker reinforcement ring 420, and selecting the material of the resonant speaker 410 as a certain type of steel, and selecting the wall thickness to be around 4 mm, the following can be obtained: Figure 4 The frequency of the vibration mode shown is 54 Hz, which means that the optimized design goal is achieved; if the wall thickness of the resonant horn 410 is increased, by adding Figure 5 The symmetrical cuts 413 of a certain depth (cuts arranged at equal intervals and lengths) shown can also achieve a local oscillation frequency of 54 Hz, thus achieving the optimized design goal.

[0096] Optimization method three, further based on the requirement that the high-pressure hollow jet pulse generated by the whistle sounder 300 excites the structural resonance vibration mode of the resonant speaker 410 at the corresponding frequency, by optimizing the arrangement of the jet hole 311 and the vent hole 312 (for example, Figure 3 ), and further enhance the effect of the compressed air jet emitted by the whirling flute sounder 300 on the air and the speaker wall under the same air supply conditions by adjusting the height of the air jet hole 311 and the air vent hole 312, optimizing the diameter of the air jet hole 311 and the air vent hole 312, adding nozzles of the air jet hole 311 and the air vent hole 312, etc., and ensure that the impact of the compressed air jet on the speaker wall directly stimulates the vibration mode selected by the optimized design, optimizes the forced vibration effect of the resonant speaker, and achieves the purpose of further enhancing the sound effect and improving the sound efficiency.

[0097] In some embodiments, since the selected Figure 4The vibration mode shown in the figure has four convex parts and four concave parts spaced apart in the circumference of the speaker when it is excited. Therefore, the whistle sounder 300 should not be used. Figure 3 The 12 rows of jet holes and vents known in BC should be arranged in a row, but Figure 3 The jet holes and vent holes are arranged in 4 rows, such as 2 rows and 4 columns or 3 rows and 4 columns, as shown in DE, and the height of the jet holes 311 and the vent holes 312 are further adjusted, the diameters of the jet holes 311 and the vent holes 312 are optimized, and nozzles of the jet holes 311 and the vent holes 312 are added for engineering optimization.

[0098] In summary, the resonant strong sound generation method, system, and optimized design method provided by the embodiments of the present disclosure utilize mechanical and acoustic theories, adopt a pneumatic horn sound generation scheme, and utilize high-pressure modulated airflow to generate a basic sound source. Based on the Bessel curve resonance theory of sound waves, a Bessel resonant horn suitable for a specific frequency is designed. Through resonance, the sound waves emitted by the horn are adjusted to standard sinusoidal sound waves with the wavefront parallel to the horn mouth surface, thereby concentrating the frequency and energy of the sound waves. To optimize the sound generation effect of the system, the resonant frequency of the Bessel resonant horn is calculated using acoustic theory, and the sound source frequency of the horn sound generator is adjusted to be consistent with the resonant frequency. The local oscillation frequency and mode shape of the horn structure are adjusted by designing a horn reinforcement ring, changing the wall thickness of the horn body, and adding horn cutouts, thereby enhancing the resonance between the horn side walls and the airflow within the cavity. Furthermore, based on the requirement that the high-pressure gas jet of the horn sound generator excites the structural resonant mode shape of the horn at the corresponding frequency, the forced vibration effect of the horn is optimized by setting the position and arrangement of the horn's air jet holes and vents, thereby improving the overall acoustic performance.

[0099] The disclosed embodiments can be used to generate low-frequency, fixed-frequency, strong sound waves with pure waveforms and good directivity. The sound waves can be emitted toward clouds in the sky to promote the collision and condensation of existing micro-droplets in the clouds, thereby achieving a rain-increasing effect. The sound waves can also be emitted toward specific areas or groups of people to achieve non-lethal area protection, crowd dispersal, and other anti-terrorism and security purposes. The sound waves can also be used for other purposes.

[0100] Throughout this specification, reference to terms such as "one embodiment," "some embodiments," "illustrative embodiments," "examples," "specific examples," or "some examples" means that the specific features, structures, materials, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present disclosure. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0101] Although the embodiments of the present disclosure have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and alterations may be made to the embodiments without departing from the principles and spirit of the present disclosure, the scope of which is defined by the claims and their equivalents.

Claims

1. A resonant strong sounding method, characterized in that: include: Produces a continuous flow of compressed air; Converting the compressed air flow into high-pressure air jet pulses according to a control signal to form a basic sound source; The basic sound source is introduced into the resonant horn. Through the synchronous excitation of the structural resonance of the horn side wall and the resonance of the air in the horn cavity, the basic sound source is subjected to fixed-frequency modulation, so that the sound wave energy is concentrated at the target frequency, a high-intensity simple harmonic sound wave is generated, and the wave surface is strictly parallel to the horn outlet and points perpendicular to the horn outlet. The radial cross-sectional curve of the horn side wall adopts a Bezier curve, and the radial cross-sectional curve of the horn side wall satisfies: Wherein, J0() is the 0th-order Bessel function, x is the independent variable of the Bessel function, F(x) is the height coordinate corresponding to the side wall of the speaker, λ is the nominal sound wave wavelength of the resonant speaker, and k0 is the nominal sound wave number of the resonant speaker.

2. A resonant strong sounding system, characterized in that: include: an air compressor for generating a continuous flow of compressed air; a control unit, the control unit being configured to generate a control signal; a whirlwind sounder connected to the air compressor and the control unit, and configured to convert the compressed air flow into high-pressure air jet pulses according to the control signal, thereby forming a basic sound source; and A sound wave modulation enhancement device, comprising a resonant horn connected to the whistle sound generator, for passing the basic sound source into the resonant horn. The basic sound source is subjected to fixed-frequency modulation through synchronous excitation of the structural resonance of the horn side wall and the resonance of the air in the horn cavity, thereby concentrating the sound wave energy at a target frequency, generating a high-intensity simple harmonic sound wave, and ensuring that the wavefront is strictly parallel to and perpendicular to the horn outlet. The radial cross-sectional curve of the horn side wall adopts a Bezier curve, and the radial cross-sectional curve of the horn side wall satisfies the following conditions: Wherein, J0() is the 0th-order Bessel function, x is the independent variable of the Bessel function, F(x) is the height coordinate corresponding to the side wall of the speaker, λ is the nominal sound wave wavelength of the resonant speaker, and k0 is the nominal sound wave number of the resonant speaker.

3. The resonant strong sounding system according to claim 2, characterized in that: The 0th order Bessel function J0(x) is: Wherein, Γ(m+1) is the gamma function, and m is a natural number from 0 to +∞.

4. The resonant strong sounding system according to claim 2, characterized in that: A horn reinforcement ring is provided at the horn outlet. The radial cross-sectional shape of the horn reinforcement ring smoothly transitions with the curve of the horn side wall and smoothly turns outward.

5. The resonant strong sound system according to claim 2, characterized in that: The whistle sounder includes a motor, a rotor driven by the motor, a stator located outside the rotor, and a cylinder disposed between the motor and the rotor. The air compressor is connected to the rotor via the cylinder. A plurality of jet holes are evenly distributed on the circumferential surface of the stator, and a plurality of vent holes are evenly distributed on the circumferential surface of the rotor. When the motor drives the movable rotor to rotate, the jet holes and the vent holes periodically overlap and separate, forming the high-pressure air jet pulses.

6. The resonant strong sound generating system according to claim 5, characterized in that: The control signal generated by the control unit includes the rotation speed of the motor.

7. A method for optimizing the design of a resonant strong sounding system, characterized in that: The resonant strong sounding system is a resonant strong sounding system according to any one of claims 2 to 6, and the optimization design method includes: Based on acoustic principles, multiple resonant frequencies corresponding to the resonant speakers of different sizes are calculated so that the sound source frequency of the rotary flute sound generator can be adjusted to one of the resonant frequencies. The control unit then adjusts the sound source frequency of the rotary flute sound generator based on the collected sound signal of the resonant strong sounding system to be consistent with the resonant frequency that achieves the optimal sounding effect.

8. An optimization design method for a resonant strong sounding system, characterized in that: The resonant strong sounding system is a resonant strong sounding system according to any one of claims 2 to 6, and the optimization design method includes: By analyzing the local oscillation modal of the structure of the resonant horn, the local oscillation frequency and vibration mode of the structure of the resonant horn are adjusted by adjusting the wall thickness of the horn side wall, adding a horn reinforcement ring at the horn outlet and / or adding a horn cutout on the horn side wall, so that the local oscillation frequency of a certain main vibration mode is consistent with a certain resonant frequency of the resonant horn.

9. An optimization design method for a resonant strong sounding system, characterized in that: The resonant strong sounding system is the resonant strong sounding system according to claim 5 or 6, and the optimization design method includes: Based on the requirement that the high-pressure air jet pulse generated by the whistle sounder excites the structural resonance vibration mode of the resonant speaker at the corresponding frequency, the positions and arrangements of the air jet holes and the vent holes in the whistle sounder are set.

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