Difference-frequency rotary whistle sound generator, sound generation method and difference-frequency rotary whistle resonance sound generation system

Abstract

The present application relates to the technical field of acoustic wave processing, and particularly relates to a differential-frequency rotary whistle sound generator, a sound generation method, and a differential-frequency rotary whistle resonance sound generation system. The differential-frequency rotary whistle sound generator has at least two groups of rotary whistle nozzles. The differential-frequency rotary whistle sound generator includes: a rotary whistle body; a stator and a rotor, both the stator and the rotor are provided with a plurality of rotary whistle nozzles, and the rotary whistle nozzles of the stator are arranged corresponding to the rotary whistle nozzles of the rotor; a driving assembly, configured to drive the rotor to rotate according to a sound generation instruction, so that when the relative pose between the rotary whistle nozzles of the stator and the rotary whistle nozzles of the rotor reaches a communicating pose, compressed air flow is released to generate pulsed sound waves of different frequencies. Thus, by providing multiple groups of rotary whistle nozzles, when the rotor is driven to rotate, according to the relative pose between the rotary whistle nozzles of the stator and the rotary whistle nozzles of the rotor, compressed air flow is released to generate pulsed sound waves of different frequencies, and the geometric attenuation of sound wave energy can be reduced.

Description

Technical Field

[0001] The present application relates to the technical field of acoustic wave processing, and particularly relates to a differential-frequency rotary whistle sound generator, a sound generation method, and a differential-frequency rotary whistle resonance sound generation system. Background Art

[0002] Sound can transmit energy and information in the form of waves. With the development of various strong sound generation technologies, the transmission distance and transmission efficiency of sound waves have been significantly improved, making the application of sound waves relatively extensive. For example, sound wave enhanced rainfall, directional sound wave bird repelling, and an airport fog elimination device using sound waves.

[0003] Currently, most of the related research on sound wave mixing is in aspects such as ultrasonic waves emitted by electroacoustic devices, their speech, and anti-riot signal synthesis. The related research work on the differential-frequency synthesis and transmission of high-strength mechanical sound waves generated by pneumatic sound sources has not been carried out. Moreover, due to the large wavelength of low-frequency sound waves, it is difficult to continue increasing the diameter of the horn. The beam directivity of the low-frequency strong sound waves directly emitted by the devices in the related technologies is insufficient, and the geometric attenuation of sound wave propagation is significant, making it difficult to meet the requirements of long-distance transmission of low-frequency strong sound waves.

[0004] Therefore, there is an urgent need for a strong sound generation device that can facilitate long-distance transmission and directionally generate high sound intensity and low-frequency sound waves. Summary of the Invention

[0005] The present application provides a differential-frequency rotary whistle sound generator, a sound generation method, and a differential-frequency rotary whistle resonance sound generation system, which solve the problem that the beam directivity of the low-frequency strong sound waves emitted in the related technologies is insufficient, and the geometric attenuation of sound wave propagation is significant, making it difficult to meet the requirements of long-distance transmission of low-frequency strong sound waves. It can reduce the geometric attenuation of sound wave energy and achieve the effect of enhancing the directional propagation ability of low-frequency strong sound waves.

[0006] In the first aspect of the embodiments of the present application, a differential-frequency rotary whistle sound generator is provided. The differential-frequency rotary whistle sound generator has at least two groups of rotary whistle nozzles, and the differential-frequency rotary whistle sound generator includes:

[0007] A rotary whistle body;

[0008] A stator and a rotor. Multiple rotary whistle nozzles are provided on both the stator and the rotor, and the rotary whistle nozzles of the stator are correspondingly arranged with the rotary whistle nozzles of the rotor;

[0009] A driving component, configured to drive the rotor to rotate according to a sound generation instruction, so that when the relative pose between the rotary whistle nozzles of the stator and the rotary whistle nozzles of the rotor reaches a communicating pose, the compressed air flow is released to generate pulse sound waves of different frequencies.

[0010] Optionally, the parameters of each rotary whistle nozzle of the stator and the rotor are obtained from the target frequency.

[0011] Optionally, the parameter includes at least one of the direction, size, cross-sectional shape, and longitudinal profile of the siren nozzle.

[0012] Optionally, the at least two groups of siren nozzles are arranged at the top or side wall of the siren body of the siren.

[0013] According to the difference-frequency siren sound generator of the embodiment of the present application, by providing multiple groups of siren nozzles and driving the rotor to rotate according to a sound generation instruction, when the relative pose between the siren nozzle of the stator and the siren nozzle of the rotor reaches a communicating pose, compressed air flow is released to generate pulse sound waves of different frequencies. Thus, the problem in the related art that the beam directivity of the emitted low-frequency strong sound wave is insufficient, the geometric attenuation of the sound wave propagation is significant, and it is difficult to meet the requirements of long-distance transmission of low-frequency strong sound waves is solved, and the geometric attenuation of the sound wave energy can be reduced, achieving the effect of enhancing the directional propagation ability of the low-frequency strong sound wave.

[0014] The second aspect of the embodiment of the present application provides a difference-frequency siren sound generation method, which uses the difference-frequency siren sound generator described in the first aspect of the embodiment. Wherein, the method includes the following steps:

[0015] Obtain the sound generation instruction;

[0016] Drive the rotor to rotate according to the sound generation instruction, so that when the relative pose between the siren nozzle of the stator and the siren nozzle of the rotor reaches a communicating pose, the compressed air flow is released to generate pulse sound waves of different frequencies.

[0017] According to the difference-frequency siren sound generation method of the embodiment of the present application, a sound generation instruction can be obtained, and the rotor is driven to rotate according to the sound generation instruction, so that when the relative pose between the siren nozzle of the stator and the siren nozzle of the rotor reaches a communicating pose, the compressed air flow is released to generate pulse sound waves of different frequencies. Thus, the problem in the related art that the beam directivity of the emitted low-frequency strong sound wave is insufficient, the geometric attenuation of the sound wave propagation is significant, and it is difficult to meet the requirements of long-distance transmission of low-frequency strong sound waves is solved, and the geometric attenuation of the sound wave energy can be reduced, achieving the effect of enhancing the directional propagation ability of the low-frequency strong sound wave.

[0018] The third aspect of the embodiment of the present application provides a difference-frequency siren resonance sound generation system, including:

[0019] The difference-frequency siren sound generator as described in the first aspect of the embodiment;

[0020] An adjustment component for adjusting the opening frequency of the at least two groups of siren nozzles so that the actual frequency of the pulse sound wave reaches a target frequency, where the target frequency is a preset fundamental frequency or difference frequency; and

[0021] A resonance propagation component, which is used to generate difference-frequency sound waves after propagating a preset distance in the target direction by utilizing the resonance effect and the acoustic parametric array effect based on pulsed sound waves reaching the target frequency.

[0022] Optionally, it further includes:

[0023] An air flow providing component, which is used to provide the compressed air flow, such as an air compressor;

[0024] A power supply component, which is used to supply power to the difference-frequency sirens generator, such as a diesel generator. Optionally, the adjustment component is a variable-frequency control box.

[0025] Optionally, the resonance propagation component is a beam control resonance horn.

[0026] Optionally, one or more of the frequency, size, line type, material, and thickness of the beam control resonance horn are obtained from the target frequency.

[0027] According to the difference-frequency sirens resonance sound generation system of the embodiments of the present application, by introducing the compressed air flow into the difference-frequency sirens generator, a pulsed compressed air jet containing two or more fundamental frequencies is emitted through two or more groups of periodically opened sirens nozzles, generating a resonance effect and an acoustic parametric array effect in the resonance propagation component, and propagating to the atmosphere through the horn outlet. After a certain distance, it is synthesized into difference-frequency sound waves. Thus, the problems in the related art that the beam directivity of the emitted low-frequency strong sound waves is insufficient, the geometric attenuation of the sound wave propagation is significant, and it is difficult to meet the requirements of long-distance transmission of low-frequency strong sound waves are solved. By applying the acoustic parametric array theory, the difference-frequency sirens generator and the resonance horn are designed, so that the fundamental frequency sound waves propagate in the near field with a small divergence angle, reducing the geometric attenuation of the sound wave energy, and forming difference-frequency sound waves with the required frequency of the difference between the fundamental frequencies in the far field, achieving the effect of strengthening the directional propagation ability of low-frequency strong sound waves.

[0028] The additional aspects and advantages of the present application will be partially given in the following description, partially become obvious from the following description, or be understood through the practice of the present application. Description of the Drawings

[0029] The above-mentioned and / or additional aspects and advantages of the present application will become obvious and easy to understand from the following description of the embodiments in conjunction with the drawings, where:

[0030] Figure 1 It is a schematic structural diagram of a difference-frequency sirens generator according to an embodiment of the present application;

[0031] Figure 2 It is a flowchart of a difference-frequency sirens sound generation method according to an embodiment of the present application;

[0032] Figure 3It is a schematic block diagram of a difference-frequency whistle resonance sound generation system provided according to an embodiment of the present application;

[0033] Figure 4 It is a structural example diagram of a difference-frequency whistle resonance sound generation system according to an embodiment of the present application;

[0034] Figure 5 It is a schematic diagram of the sound effect propagation of a difference-frequency whistle resonance sound generation system according to an embodiment of the present application;

[0035] Figure 6 It is a schematic diagram of the arrangement of the rotor and stator when the top and side of the difference-frequency whistle generator discharge air. Detailed implementation manners

[0036] The embodiments of the present application will be described in detail below. The examples of the embodiments are shown in the drawings, where the same or similar reference numerals denote the same or similar elements or elements with the same or similar functions from beginning to end. The embodiments described below with reference to the drawings are exemplary and are intended to explain the present application, but should not be construed as limiting the present application.

[0037] The difference-frequency whistle generator, sound generation method, and difference-frequency whistle resonance sound generation system according to the embodiments of the present application will be described below with reference to the drawings. In view of the problem in the related art mentioned in the above background art that the beam directivity of the low-frequency strong sound wave emitted is insufficient, the geometric attenuation of the sound wave propagation is significant, and it is difficult to meet the requirements of long-distance transmission of low-frequency strong sound waves, the present application provides a difference-frequency whistle generator. By setting multiple groups of whistle nozzles and driving the rotor to rotate according to a sound generation instruction, when the relative pose of the whistle nozzle of the stator and the whistle nozzle of the rotor reaches a communicating pose, compressed air flow is released to generate pulsed sound waves of different frequencies. Thereby, the problem in the related art that the beam directivity of the low-frequency strong sound wave emitted is insufficient, the geometric attenuation of the sound wave propagation is significant, and it is difficult to meet the requirements of long-distance transmission of low-frequency strong sound waves is solved, and the geometric attenuation of the sound wave energy can be reduced, achieving the effect of strengthening the directional propagation ability of the low-frequency strong sound wave.

[0038] Specifically, Figure 1 It is a structural schematic diagram of a difference-frequency whistle generator provided by an embodiment of the present application. In this embodiment, the difference-frequency whistle generator has at least two groups of whistle nozzles.

[0039] As Figure 1 shown, the difference-frequency whistle generator 100 includes: a whistle body 101, a stator 102, a rotor 103, and a driving assembly 104.

[0040] Among them, both the stator 102 and the rotor 103 are provided with a plurality of sirens nozzles. The sirens nozzles of the stator 102 (such as the air jet nozzle 1021) and the sirens nozzles of the rotor 103 (such as the air vent 1031) are arranged correspondingly; the driving assembly 104 is used to drive the rotor 103 to rotate according to the sound generation instruction, so that when the relative pose between the sirens nozzles of the stator 102 and the sirens nozzles of the rotor 103 reaches the communicating pose, compressed air flow is released to generate pulsed sound waves of different frequencies.

[0041] Among them, in some embodiments, the parameters of each sirens nozzle of the stator 102 and the rotor 103 are obtained from the target frequency.

[0042] Among them, in some embodiments, the parameters include at least one of the direction, size, cross-sectional shape, and longitudinal profile of the sirens nozzle. That is to say, in the embodiments of the present application, one or more parameters of the sirens nozzle can be selected according to actual needs, such as only selecting the three parameters of the direction, size, and cross-sectional shape of the sirens nozzle, or simultaneously selecting the direction, size, cross-sectional shape, and longitudinal profile of the sirens nozzle.

[0043] Specifically, the differential frequency sirens sound generator 100 is designed based on the mode of the air flow modulation type sound generator. High-pressure gas is supplied from the middle, the rotor 103 and the stator 102 are installed on the upper part, and the rotor 103 and the stator 102 are punched in the same phase. The driving assembly 104 can be a motor, and the motor drives the rotor 103 to rotate through the driving shaft 105. When the rotor 103 rotates to correspond to the position of the sirens nozzle of the stator 102, high-pressure gas is released, and it is closed when they are out of alignment. One pulse sound wave is generated for each opening and closing. Among them, the driving assembly 104 can be placed at the bottom of the differential frequency sirens sound generator 100, and the rotor 103 is driven to rotate by passing the driving shaft 105 through the cylinder 106. The stator 102 always remains fixed, and pulse sound waves are generated by the opening and closing of the air vent 1031 and the air jet nozzle 1021 of the rotor 103 and the stator 102 in the same phase.

[0044] According to the differential frequency sirens sound generator proposed by the embodiments of the present application, by setting multiple groups of sirens nozzles and driving the rotor to rotate according to the sound generation instruction, when the relative pose between the sirens nozzles of the stator and the sirens nozzles of the rotor reaches the communicating pose, compressed air flow is released to generate pulsed sound waves of different frequencies. Thus, the problem that the beam directivity of the low-frequency strong sound waves emitted in the related art is insufficient, the geometric attenuation of the sound wave propagation is significant, and it is difficult to meet the requirements of long-distance transmission of low-frequency strong sound waves is solved. The geometric attenuation of the sound wave energy can be reduced, and the effect of strengthening the directional propagation ability of the low-frequency strong sound waves can be achieved.

[0045] Next, a differential frequency sirens sound generation method according to an embodiment of the present application will be described with reference to the accompanying drawings.

[0046] Figure 2It is a flowchart of the differential frequency whistle sound generation method according to an embodiment of the present application. The differential frequency whistle sound generation method uses Figure 1 the differential frequency whistle sound generator shown in the embodiment.

[0047] As Figure 2 shown, the differential frequency whistle sound generation method includes the following steps:

[0048] S201, obtain a sound generation instruction.

[0049] S202, drive the rotor to rotate according to the sound generation instruction, so that when the relative pose between the whistle nozzle of the stator and the whistle nozzle of the rotor reaches the communicating pose, release the compressed air flow to generate pulsed sound waves of different frequencies.

[0050] It should be noted that the foregoing explanation of the embodiment of the differential frequency whistle sound generator also applies to the differential frequency whistle sound generation method of this embodiment, and will not be elaborated here.

[0051] According to the differential frequency whistle sound generation method proposed by the embodiment of the present application, a sound generation instruction can be obtained, and the rotor can be driven to rotate according to the sound generation instruction, so that when the relative pose between the whistle nozzle of the stator and the whistle nozzle of the rotor reaches the communicating pose, release the compressed air flow to generate pulsed sound waves of different frequencies. Thus, the problem that the beam directivity of the low-frequency strong sound wave emitted in the related art is insufficient, the geometric attenuation of the sound wave propagation is significant, and it is difficult to meet the requirements of long-distance transmission of low-frequency strong sound waves is solved, and the geometric attenuation of the sound wave energy can be reduced, achieving the effect of strengthening the directional propagation ability of the low-frequency strong sound wave.

[0052] Furthermore, an embodiment of the present application also proposes a differential frequency whistle resonance sound generation system.

[0053] Specifically, as Figure 3 shown, Figure 3 is a block diagram of a differential frequency whistle resonance sound generation system provided by an embodiment of the present application. The differential frequency whistle resonance sound generation system 10 includes: Figure 1 the differential frequency whistle sound generator 100, an adjustment component 200, and a resonance propagation component 300 shown in the embodiment.

[0054] Among them, the differential frequency whistle sound generator 100 has at least two groups of whistle nozzles for emitting pulsed sound waves using compressed air flow. The adjustment component 200 is used to adjust the opening frequency of at least two groups of whistle nozzles so that the actual frequency of the pulsed sound wave reaches the target frequency, where the target frequency is a preset fundamental frequency or a differential frequency. The resonance propagation component 300 is used to generate a differential frequency sound wave after propagating a preset distance in the target direction based on the pulsed sound wave that reaches the target frequency, using the resonance effect and the acoustic parametric array effect.

[0055] Among them, the preset fundamental frequency and difference frequency can both be frequencies preset by the user, frequencies obtained through a limited number of experiments, or frequencies obtained through a limited number of computer simulations, and no specific limitation is made here.

[0056] Optionally, in some embodiments, the adjustment component 200 can be a variable frequency control box.

[0057] Optionally, in some embodiments, the resonant propagation component 300 can be a beam control resonant horn.

[0058] Specifically, as shown in Figure 4 , the difference frequency whistle generator 100 can convert the compressed air flow into high-pressure air jet pulses (i.e., pulsed sound waves) of two different frequencies (i.e., the preset fundamental frequency or difference frequency) according to the control signal generated by the adjustment component 200, thereby forming a basic sound source composed of two sound waves of different frequencies. The resonant propagation component 300 can introduce the generated basic sound source into the resonant horn, and the resonant frequency of the resonant horn can be approximately set within the range of the fundamental frequency or accurately set as the difference frequency of the fundamental frequency. When set to the fundamental frequency, the basic sound source is modulated and enhanced through the resonant effect of the horn, and a high-intensity harmonic sound wave of the fundamental frequency is emitted from the horn outlet; when set to the difference frequency of the fundamental frequency, through the resonant effect and impedance effect of the horn, two or more sound waves of the fundamental frequency generate a strong parametric array effect in the resonant horn, causing the sound wave energy to transfer more to the difference frequency (i.e., the target frequency).

[0059] After the sound wave is emitted from the resonant horn outlet and enters the open atmosphere, it continues to propagate in the same direction. Since the fundamental frequency is higher, the beam angle is smaller, and the geometric attenuation in the open atmosphere is smaller, it is beneficial for the long-distance transmission of sound wave energy. After the sound wave propagates a certain distance, when the combined effect in the resonant horn and the atmosphere reaches the parametric array length, the sound wave energy is concentrated on the difference frequency, and the sound wave then diffuses and attenuates according to the beam angle of the difference frequency sound wave.

[0060] As an example, multiple groups of fundamental frequencies can be used to form higher-order difference frequencies, thereby forming lower-frequency sound waves at a long distance. For example, when the 5 fundamental frequencies are 640 Hz, 820 Hz, 1000 Hz, 1200 Hz, and 1400 Hz respectively, the first-order difference frequency sound waves are 180 Hz and 200 Hz, and a 20 Hz low-frequency sound wave will be further generated at the far end.

[0061] It should be noted that the variable frequency control box can generate a control signal, which can be used to set and adjust the motor speed in the beat frequency whistle generator 100 and reach the optimal operating frequency, so as to control the frequencies of two or more basic sound sources in a fixed ratio, and then control the frequency of the beat frequency sound wave, and make the frequency match the beam control resonant horn; the beam control resonant horn is a sound wave modulation enhancement device. According to the theory of sound wave focusing and resonance in the Bessel curve horn cavity, a curved surface suitable for the resonance of sound waves with a specific frequency is designed, and it is processed into a horn entity using metal materials. When working, the pulse wave emitted by the whistle is modulated into a high-intensity simple harmonic sound wave through the resonance of the air in the horn cavity.

[0062] To facilitate those skilled in the art to further understand the beat frequency whistle resonance sound system 10 of the embodiments of the present application, the beat frequency whistle resonance sound system 10 of the embodiments of the present application, as well as the design of the basic frequency, the jet opening of the beat frequency whistle, and the resonant horn in the beat frequency whistle resonance sound system 10 will be elaborated in detail below in conjunction with specific embodiments.

[0063] First, the power supply component, the resonance propagation component 300 of the beat frequency whistle resonance sound system 10, and the operation mode of the beat frequency whistle resonance sound system 10 will be elaborated in conjunction with specific embodiments.

[0064] Furthermore, in some embodiments, as Figure 4 shown, the above-mentioned beat frequency whistle resonance sound system 10 further includes: an air flow providing component 400 and a power supply component 500. Among them, the air flow providing component 400 is used to provide the compressed air flow, and the air flow providing component 400 can be an air compressor; the power supply component 500 is used to supply power to the beat frequency whistle generator 100, and the power supply component 500 can be a diesel generator.

[0065] For example, the compressed air flow generated by the air flow providing component 400 can be a continuous compressed air flow; the embodiments of the present application can use a diesel generator or other power supplies to supply power to drive the driving component 104 (such as a motor) of the beat frequency whistle generator 100 to drive the rotor 103 to rotate.

[0066] Furthermore, as Figure 4 shown, when the resonance propagation component 300 is a beam control resonant horn, the beam control resonant horn can include: a resonant horn 301, a horn inlet 302, a horn outlet 303, and a horn bracket 304. When the resonance propagation component 300 is a beam control resonant horn, the radial cross-sectional curve of the side wall of the beam control resonant horn satisfies:

[0067]

[0068]

[0069]

[0070] Among them, J0(x) is the Bessel function of order 0, x is the independent variable of the Bessel function; Γ is the gamma function, m is a natural number from 0 to +∞; F(x) is the height coordinate corresponding to the side wall of the resonant horn; λ is the nominal acoustic wavelength of the resonant horn, and its relationship with the sound speed C and the nominal frequency f is λ = C / f; k0 is the nominal acoustic wave number of the resonant horn, k0 = 2πf / C = 2π / λ; R(x) is the radial coordinate corresponding to the side wall of the resonant horn.

[0071] It should be noted that in the embodiments of the present application, multiple sets of the difference-frequency whistle resonant sound generation systems can be formed into an array, and the synchronous signal or control signal technology can be used to control the sound waves emitted by the sound generation systems to be in the same or program-specified phase, so as to enhance the sound generation effect of the total system, or be formed into a phase control array (phased array) sound generation system for controlling the overall direction of the strong sound wave.

[0072] Considering the change in the direction of the Bessel function curve, the value range of x can be 1 to 2.4; the nominal frequency is taken as f = 87 Hz, and the sound speed is taken as C = 340 m / s; according to the above formula calculation, the diameter of the horn outlet of the resonant horn corresponding to the nominal frequency of 87 Hz is 2988 mm, and the main body height is 1906 mm.

[0073] In summary, the operation mode of the difference-frequency whistle resonant sound generation system 10 can be as follows: The air compressor generates a continuous compressed air flow, which is introduced into the difference-frequency whistle sound generator 100 through the pressure pipeline; in the embodiments of the present application, a diesel generator or other power supply can be used to supply power to drive the driving component 104 (such as a motor) of the difference-frequency whistle sound generator 100 to drive the rotor 103 to rotate; the rotor 103 and the stator 102 respectively open and close through two groups of differently arranged nozzles (i.e., whistle nozzles) to form two different-frequency sound waves; and the rotation speed of the rotor 103 is adjusted through the adjustment component 200 (such as a frequency conversion control box) to control the opening frequency of the air jet port 1021 and thus control the frequency of the sound wave; the compressed air introduced by the air compressor enters the interior of the housing of the difference-frequency whistle sound generator 100, and the relatively large pressure regulation space inside the rotor 103 can keep the air pressure basically stable; as the rotor 103 rotates, during the process that the air vent 1031 on the side wall of the rotor 103 and the air jet port 1021 on the side wall of the stator 102 change from non-coincidence to partial coincidence, to complete coincidence, then to partial coincidence, and finally to non-coincidence, a high-pressure air jet pulse is generated outward once in the compressed air inside the rotor 103, impacting the air and the side wall of the horn in the cavity of the resonant propagation component 300 (such as a beam control resonant horn). Through the synchronous excitation of the structural resonance of the horn side wall and the air resonance in the horn cavity, a strong fixed-frequency modulation effect is generated, so that the sound wave energy is concentrated at a specific frequency, generating two different-frequency simple harmonic sound waves, and making the wave surface strictly parallel to the horn outlet and the direction perpendicular to the horn outlet.

[0074] Thus, for two fundamental frequency waves propagating in the same direction, the fundamental frequency is relatively high in the near field, and the beam angle is relatively small. The obtained difference frequency wave in the far field has a relatively low frequency and slow attenuation. When the two fundamental frequency waves propagate to the length of the parametric array, the acoustic wave synthesis process is completed, and then it starts to spread according to the beam angle corresponding to the difference frequency.

[0075] Secondly, the design of the fundamental frequency, the whistle nozzle, and the resonant horn in the difference frequency whistle resonant sound generation system 10 will be elaborated in detail in combination with specific embodiments.

[0076] Specifically, in the embodiments of the present application, the distribution of the whistle nozzles on the rotor 103 and the stator 102 of the difference frequency whistle generator 100 can be designed according to the principle of the acoustic parametric emission array to modulate the compressed air flow and generate two high-pressure air jet pulses with different frequencies. Each small opening is a sound source, and all sound sources are distributed at intervals in two (or more) groups with different frequencies. The fundamental frequency of each group of sound sources is relatively high, and the acoustic waves of the fundamental frequency propagate with the corresponding divergence angle, with a relatively small beam angle and less geometric attenuation loss. The acoustic waves of the fundamental frequency gradually combine into low-frequency difference frequency acoustic waves in the resonant horn and the atmosphere, and reach the maximum sound intensity of the difference frequency.

[0077] Furthermore, the design of the fundamental frequency and the difference frequency is as follows:

[0078] There is a great space for selection and optimization of the fundamental frequency whose frequency difference is equal to the target frequency. The main objectives of the fundamental frequency design are: the frequency of the difference frequency acoustic wave, the target distance of the difference frequency acoustic wave, the sound pressure level of the difference frequency acoustic wave at the target distance, and the lateral action range of the difference frequency acoustic wave at the target distance. The factors to be considered in the fundamental frequency design include: the geometric attenuation characteristics of the fundamental frequency, mechanical performance factors such as the rotation speed of the difference frequency whistle, pulse jet sound generation efficiency factors such as the opening size and opening and closing time of the difference frequency whistle, resonance and impedance factors of the resonant horn, and atmospheric absorption attenuation factors. The fundamental frequency optimization should achieve the design objectives, fully consider all important factors, satisfy more secondary factors, and generally use the numerical simulation method of acoustic, fluid, and mechanical coupling for optimization calculation and conduct sufficient prototype tests.

[0079] For example, assume that the rotational frequency of the motor is f0 Hz. The motor drives the drive shaft to rotate the rotor 103. When the motor rotates one circle, the inner-rotor whistle nozzle (i.e., the air vent) and the stator whistle nozzle (i.e., the air jet nozzle) open and close n1 times, and the outer-rotor whistle nozzle (i.e., the air vent) and the stator whistle nozzle (i.e., the air jet nozzle) open and close n2 times. The sound wave frequencies generated by the inner and outer circles are n1×f0 Hz and n2×f0 Hz respectively. According to the theory of acoustic parametric arrays, by utilizing the nonlinear characteristics of sound wave propagation in a medium, from two fundamental frequency waves propagating in the same direction (the frequencies of the two fundamental frequency waves are f1 and f2 respectively, and f2>f1), a difference frequency wave (the frequency f d =f2 - f1) and a sum frequency wave (f1 + f2) can be obtained in the far field. The frequency of the sum frequency wave is relatively high and decays rapidly; the frequency of the difference frequency wave is relatively low and decays slowly. When the propagation reaches the length of the acoustic parametric array, the sound intensity is the largest and then gradually decays. The schematic diagram of the sound propagation effect of the difference frequency whistle resonance sound system can be as Figure 5 shown.

[0080] Therefore, the whistle nozzle is located at the top of the difference frequency whistle and is divided into two circles, the inner and the outer. The calculation methods for its fundamental frequency and difference frequency are as follows:

[0081] Inner-circle fundamental frequency: f1 = n1×f0;

[0082] Outer-circle fundamental frequency: f2 = n2×f0;

[0083] Difference frequency sound wave frequency: f d =(n2 - n1)×f0;

[0084] where f0 is the rotational frequency of the motor, f0 = N / 60, N is the motor speed (unit: rpm), n1 and n2 respectively correspond to the number of openings in the inner and outer circles, and n1 < n2.

[0085] As a possible implementation method, assume that the whistle nozzle (air jet nozzle) is located at the top of the difference frequency whistle generator. The outer diameter of the stator is 360 mm, and 2 circles of openings are evenly distributed at 135 mm and 110 mm in the radial direction, with a diameter of 15 mm. There are 20 openings in the outer circle and 18 openings in the inner circle. A large-diameter bearing with an outer diameter of 190 mm is used to support the rotating disk to bear the upward thrust and rotational inertia force to ensure its smooth and uniform rotation. The motor frequency is 25 Hz. Accordingly, the outer-circle air jet frequency is 500 Hz, the inner-circle is 450 Hz, and the difference frequency is 50 Hz.

[0086] Here, assume that the frequency of the beam control resonance horn is set as the fundamental frequency, that is, the beam control resonance horn has better acoustic performance for the fundamental frequencies of 500 Hz and 450 Hz. Then the parametric effect is mainly completed in the open atmosphere. At this time, the length L of the parametric array 0C The calculation formula is as follows:

[0087]

[0088] α = 4×10 -7 ×f 2 + 0.0038×f + 0.1454; (5)

[0089] Wherein, α is the attenuation coefficient of sound waves in air, calculated by Equation (5), and Equation (5) is the regression equation of α and f according to the national standard (GB / T 17247.1-2000) "Outdoor Sound Propagation Attenuation" under standard atmospheric pressure (101.325 kPa), temperature 10°C, and relative humidity 80%, and f is the corresponding sound wave frequency.

[0090] When the relative humidity is 80% and the atmospheric temperature is 10°C, the length L of the parametric array corresponding to the fundamental waves of 500 Hz and 450 Hz 0C is 273.9 m, that is, the synthesis of the 50 Hz difference frequency sound wave is completed at 273.9 m from the sound source.

[0091] Calculate the geometric divergence of sound waves according to the law of conservation of energy formula and the sound intensity calculation formula (6), and calculate the atmospheric absorption according to Equation (7).

[0092]

[0093] p t = αs; (7)

[0094] Wherein, I is the sound intensity, p is the instantaneous sound pressure, ρ0 is the atmospheric density, c0 is the speed of sound; α α is the attenuation coefficient at a relative humidity of 80% and an atmospheric temperature of 10°C, calculated by Equation (5), s is the propagation distance, calculated according to the length of the 50 Hz difference frequency parametric array of 273.9 m.

[0095] Assume that the sound pressure level at the outlet of the single-frequency siren is 150 dB, the outlet frequency is 50 Hz, the geometric attenuation at 273.9 m is 52.2 dB, the atmospheric absorption is 0.02 dB, the remaining sound pressure level is 97.77 dB, and the diffusion area is 0.471 km 2 ; Assume that the sound pressure level at the outlet of the difference frequency siren is 150 dB, composed of 500 Hz and 450 Hz frequencies, and the sound pressure levels of the two frequencies are 144 dB respectively. At 273.9 m, the geometric attenuation of 500 Hz is 44.67 dB, the atmospheric absorption is 0.53 dB, and the remaining sound pressure level is 98.80 dB; the geometric attenuation of 450 Hz is 45.63 dB, the atmospheric absorption is 0.49 dB, and the remaining sound pressure level is 97.89 dB; the remaining total sound pressure level is 104.37 dB, and the end plane area is 0.104 km 2, the sound pressure level of the difference - frequency whistle generator is 6.6 dB higher than that of the single - frequency whistle generator at 273.9 m at the parametric array end. At the plane of the acoustic parametric array end, the fundamental frequency wave and the sum - frequency wave of the two fundamental frequency waves have basically attenuated, and only the difference - frequency wave continues to emit forward. At 1000 m, the sound pressure level of the single - frequency whistle generating system is 86.47 dB, and the sound pressure level of the difference - frequency whistle is 87.62 dB; at 2000 m, the sound pressure level of the single - frequency whistle is 80.38 dB, and the sound pressure level of the difference - frequency whistle is 81.08 dB; at 3000 m, the sound pressure level of the single - frequency whistle is 76.79 dB, and the sound pressure level of the difference - frequency whistle is 77.26 dB. The remaining sound pressure levels of the difference - frequency whistles are all greater than those of the single - frequency whistles.

[0096] Furthermore, the design of the whistle nozzle is as follows:

[0097] Consideration factors: the opening direction of the whistle nozzle, the total opening area, the size of a single opening, the cross - sectional shape of the opening, and the longitudinal - sectional line shape of the opening. Among them, the opening direction (top or circumferential side) is designed for joint optimization with the resonant horn to achieve the coordination of sound - generating efficiency and acoustic impedance performance; the total opening area, the size of a single opening, the cross - sectional shape of the opening, and the longitudinal - sectional line shape of the opening are used to optimize the sound - generating efficiency of the whistle under a certain air supply or at a certain target sound intensity.

[0098] As a possible implementation method, in some embodiments, at least two groups of whistle nozzles (i.e., the positions of the jet nozzles) of the difference - frequency whistle generator 100 are located at the top of the whistle, as shown in Figure 6 (a) and Figure 6 (b). Among them, Figure 6 (a) is a schematic diagram of the stator when the whistle nozzle (jet nozzle) position is at the top of the whistle, Figure 6 (b) is a schematic diagram of the rotor when the whistle nozzle (jet nozzle) position is at the top of the whistle. The number of inner - ring orifices is less than that of the outer - ring orifices. The inner - ring and outer - ring whistle nozzles (jet nozzles) respectively form sound sources of two or more groups of frequencies, and the sound - generating frequency of the inner - ring orifices is less than that of the outer - ring orifices.

[0099] As another possible implementation method, in some embodiments, at least two groups of whistle nozzles (i.e., the positions of the jet nozzles) of the difference - frequency whistle generator 100 are located on the side wall of the whistle, as shown in Figure 6 (c) and Figure 6 (d). Among them, Figure 6 (c) is a schematic diagram of the stator when the whistle nozzle (jet nozzle) position is on the side wall of the whistle, Figure 6(d) Schematic diagram of the rotor when the position of the whistle nozzle (air jet nozzle) is on the side wall of the whistle, divided into two or more rows up and down, with different numbers of nozzles. The two or more rows up and down have different sounding frequencies due to different numbers of nozzles. When there are multiple circles or rows of whistle nozzles (air jet nozzles), the grouped arrangement or spaced arrangement of the whistle nozzles (air jet nozzles) can be determined according to the optimization calculation.

[0100] Furthermore, the design of the beam control resonant horn is as follows:

[0101] Consideration factors: the frequency of the beam control resonant horn, the size of the beam control resonant horn, the linear type of the beam control resonant horn, the material and thickness of the beam control resonant horn, etc. Among them, the frequency of the beam control resonant horn can be set to the fundamental frequency or the difference frequency. When the difference frequency is adopted, the length of the parametric array in the atmosphere can be reduced, but the advantage of the small geometric attenuation of the fundamental frequency sound wave is reduced.

[0102] That is to say, one or more of the frequency, size, linear type, material and thickness of the beam control resonant horn can be obtained from the target frequency, so as to use the size, linear type, material and thickness of the beam control resonant horn to optimize the acoustic performance of the horn and achieve the coordination of the resonance effect and the acoustic impedance performance.

[0103] According to the difference-frequency whistle resonance sound generation system proposed in the embodiments of the present application, by introducing a compressed air flow into the difference-frequency whistle sound generator, a pulsed compressed air jet containing two or more fundamental frequencies is emitted through two or more groups of whistle nozzles that are periodically opened, generating a resonance effect and an acoustic parametric array effect in the resonance propagation component, and propagating to the atmosphere through the horn outlet. After a certain distance, it is synthesized into a difference-frequency sound wave. Thus, the problem in the related art that the beam directivity of the emitted low-frequency strong sound wave is insufficient, the geometric attenuation of the sound wave propagation is significant, and it is difficult to meet the requirements of long-distance transmission of low-frequency strong sound waves is solved. By applying the acoustic parametric array theory, the difference-frequency whistle sound generator and the resonant horn are designed, so that the fundamental frequency sound wave propagates with a small divergence angle in the near field, reducing the geometric attenuation of the sound wave energy, and forming a difference-frequency sound wave with the required frequency difference of the fundamental frequencies in the far field, achieving the effect of strengthening the directional propagation ability of the low-frequency strong sound wave.

[0104] In the description of this specification, the descriptions referring to terms such as "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. mean that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of this application. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or N embodiments or examples. In addition, without contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0105] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one of the features. In the description of this application, the meaning of "N" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0106] It should be understood that each part of this application can be implemented by hardware, software, firmware, or a combination of them. In the above embodiment, the N steps or methods can be implemented by software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented by hardware, as in another embodiment, any one or a combination of the following technologies well known in the art can be used: discrete logic circuits with logic gate circuits for implementing logic functions on data signals, application specific integrated circuits with appropriate combinational logic gate circuits, programmable gate arrays (PGAs), field programmable gate arrays (FPGAs), etc.

[0107] Those of ordinary skill in the art of this technology can understand that all or part of the steps carried by the method for implementing the above embodiment can be completed by a program instructing relevant hardware, and the program can be stored in a computer-readable storage medium. When the program is executed, it includes one or a combination of the steps of the method embodiment.

[0108] In addition, each functional unit in various embodiments of this application can be integrated in a processing module, or each unit can exist physically alone, or two or more units can be integrated in a module. The above integrated module can be implemented in the form of hardware or in the form of a software functional module. When the integrated module is implemented in the form of a software functional module and sold or used as an independent product, it can also be stored in a computer-readable storage medium.

[0109] Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present application. Those of ordinary skill in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present application.

Claims

1. A difference-frequency rotary whistle resonance sound generation system, characterized in that, Including: An adjustment component for adjusting the opening frequencies of at least two sets of whistle nozzles so that the actual frequency of the pulsed sound wave reaches a target frequency, where the target frequency is a preset fundamental frequency or difference frequency; and A resonant propagation component for generating a difference frequency sound wave after propagating a preset distance in a target direction based on the pulsed sound wave reaching the target frequency by utilizing the resonance effect and the acoustic parametric array effect; A difference frequency whistle sound generator, the difference frequency whistle sound generator having at least two sets of whistle nozzles, the difference frequency whistle sound generator including: A whistle body; A stator and a rotor, both the stator and the rotor being provided with a plurality of whistle nozzles, and the whistle nozzles of the stator being correspondingly arranged with the whistle nozzles of the rotor; A driving component for driving the rotor to rotate according to a sounding instruction so that when the relative postures of the whistle nozzles of the stator and the rotor reach a communicating posture, a compressed air flow is released to generate pulsed sound waves of different frequencies.

2. The system according to claim 1, wherein It further includes: An air flow providing component for providing a compressed air flow, being an air compressor; A power supply component for supplying power to the difference frequency whistle sound generator, being a diesel generator.

3. The system according to claim 1 or 2, characterized in that, The adjustment component is a variable frequency control box.

4. The system according to claim 3, wherein The resonant propagation component is a beam control resonant horn.

5. The system according to claim 4, wherein Wherein, One or more of the frequency, size, linear type, material and thickness of the beam control resonant horn are obtained from the target frequency.

6. The system according to claim 1, wherein The parameters of each whistle nozzle of the stator and the rotor are obtained from the target frequency.

7. The system according to claim 6, characterized in that, The parameters include at least one of the direction, size, cross-sectional shape and longitudinal profile line shape of the whistle nozzle.

8. The system according to claim 1, wherein The at least two sets of whistle nozzles are arranged on the whistle top or the whistle side wall of the whistle body.

9. A differential frequency rotary whistle sound generation method, characterized in that, Using the system according to any one of claims 1-8, wherein the method includes the following steps: Obtaining the sounding instruction; Driving the rotor to rotate according to the sounding instruction so that when the relative postures of the whistle nozzles of the stator and the rotor reach a communicating posture, the compressed air flow is released to generate pulsed sound waves of different frequencies.

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