Underwater millihertz earthquake sound source transducer and low-frequency sound wave generation method

Abstract

The invention discloses an underwater millihertz earthquake sound source transducer and a low-frequency sound wave generation method, the transducer comprises a shell assembly, a high-frequency acoustic transducer, an acoustic medium, a magnetic field generation assembly, an electric field generation assembly and acoustic rubber, and the shell assembly is internally provided with a cavity; the high-frequency acoustic transducer is arranged at the first end of the cavity, the acoustic rubber is arranged at the second end of the cavity, and the acoustic medium is arranged between the high-frequency acoustic transducer and the acoustic rubber; the magnetic field generation assembly is arranged on the shell assembly and used for generating a magnetic field covering the acoustic medium; the electric field generating assembly is arranged on the shell assembly and used for generating an alternating current electric field covering the acoustic medium; the acoustic medium is oscillation fluid. Fluid is driven through an electric field and a magnetic field, sound waves are in nonlinear coupling with the fluid, millihertz sound waves are generated while the small size is kept, modulation sound waves can be generated, and the application requirements of prospecting, ultra-long-distance detection and the like are effectively met.

Description

Technical Field

[0001] The invention relates to the technical field of transducers, in particular to an underwater millihertz seismic sound source transducer and a low-frequency sound wave generation method. Background Art

[0002] In underwater environments, sound becomes the primary means of navigation, ranging, and communication due to the limited propagation distance of radio frequency waves and light waves. The propagation characteristics of sound in water show that the higher the frequency, the more obvious the attenuation, and the attenuation coefficient is proportional to the square of the frequency. This means that high-frequency sounds will quickly attenuate in water, so low-frequency sounds are particularly important in order to achieve long-distance propagation. However, the low-frequency speakers currently on the market have the following shortcomings: 1. The size of existing speakers is too large, which is not convenient to carry, transport, install and integrate. Effective low-frequency speakers usually require a large volume because the sound pressure output is proportional to the surface area and vibration speed of the object. This results in the existing low-frequency sound sources often being large devices that are not convenient to carry, transport, install and integrate. In order to achieve a low-frequency sound source of 10Hz, the speakers sold on the market need to reach a diameter of 20 cm and a length of 1 meter; in order to achieve a low-frequency sound source of 1Hz, the diameter needs to reach 5 meters and the length needs to reach 9 meters, which is much larger than a standard container, making the volume of the equipment too large. This volume limits the application of speakers in different scenarios, especially in cases where rapid deployment or movement is required, and customers may give up using them due to their inconvenience. In many application scenarios, multiple low-frequency speakers need to be combined into an array to achieve better acoustic effects. If the size of the speaker is too large, it is not convenient for integration and layout.

[0003] 2. The cost of existing speakers is too high, which reduces the audience and sales. Due to the large size of existing speakers, the cost of raw materials and equipment required also increases accordingly. This directly leads to high market prices and maintenance prices for low-frequency speakers, limiting the scope of potential users. The high price makes it difficult for many scientific research teams and institutions to afford it, reducing the market acceptance and sales of the product. Speakers sold on the market that reach a minimum frequency of 10Hz are priced at 1 million yuan; those that reach a minimum frequency of 2Hz are priced at 2 million yuan; speakers that reach a minimum frequency of 1Hz are not sold to the public, indicating that their technology and manufacturing difficulties are extremely high, and there are almost no products available on the market.

[0004] 3. The functions of existing speakers are limited and cannot meet the needs of all scenarios. Although low-frequency speakers are crucial in underwater applications, the functions of existing products are often relatively single and cannot meet the needs of all scenarios. In sonar and communication systems, in addition to low-frequency sources, medium-frequency and high-frequency sources are also required to provide greater bandwidth and higher data transmission capabilities. Developing broadband, high-power, compact low-frequency speakers is a technical challenge faced by other companies. It is worth mentioning that there are no speakers on the market that can reduce the lowest frequency to below 1Hz. Summary of the invention

[0005] In view of the deficiencies in the above-mentioned prior art, the present invention provides an underwater millihertz seismic sound source transducer and a low-frequency sound wave generation method, which are small in size and can generate a wide range of sound frequencies, and can even generate millihertz sound waves, which can effectively meet the application requirements of prospecting, ultra-long-range detection, etc.

[0006] To achieve the above object, the present invention provides an underwater millihertz seismic sound source transducer, comprising a shell component, a high-frequency acoustic transducer, an acoustic medium, a magnetic field generating component, an electric field generating component and an acoustic rubber, wherein a cavity is provided in the shell component; The high-frequency acoustic transducer is arranged at a first end of the cavity, the acoustic rubber is arranged at a second end of the cavity, and the acoustic medium is arranged between the high-frequency acoustic transducer and the acoustic rubber; The magnetic field generating assembly is arranged on the shell assembly and is used to generate a magnetic field covering the acoustic medium; The electric field generating component is arranged on the shell component, and is used to generate an alternating electric field covering the acoustic medium; The acoustic medium is an oscillating fluid.

[0007] In one embodiment, the electric field generating assembly includes two high-frequency electrodes, and the two high-frequency motors are arranged on the left and right sides of the cavity; The magnetic field generating assembly comprises two magnets, and the two magnets are arranged on the upper and lower sides of the cavity.

[0008] In one embodiment, the magnet is a strong magnet or an electromagnet.

[0009] In one embodiment, the housing assembly includes an end housing, an outer housing and an inner frame; The outer shell and the inner frame are both rectangular cylindrical structures with openings at both ends, the end shell is arranged at the first end of the outer shell, the acoustic rubber is arranged at the second end of the outer shell, and the high-frequency acoustic transducer is arranged on the inner wall of the outer shell; The inner frame is embedded in the outer shell, and the opening of the first end of the inner frame faces the high-frequency acoustic transducer, and the opening of the second end faces the acoustic rubber; The two high-frequency electrodes are respectively arranged on the side walls of the left and right sides of the inner frame, and the two magnets are respectively arranged between the outer walls of the upper and lower sides of the inner frame and the inner wall of the outer shell.

[0010] In one embodiment, the cross-section of the acoustic rubber is a convex structure as a whole, the convex portion of which is sealed and embedded in the opening of the second end of the outer shell, and the remaining portion abuts against the inner wall of the second end of the outer shell.

[0011] In one embodiment, the inner walls on the left and right sides of the inner frame are provided with slots, the two high-frequency electrodes are fixedly embedded in the slots on the corresponding sides, and the side walls on the left and right sides of the inner frame are provided with cable holes.

[0012] To achieve the above object, the present invention also provides a method for generating low-frequency sound waves, using the above underwater millihertz seismic sound source transducer; The low-frequency sound wave generation method comprises the following steps: After encapsulating the acoustic medium in the space, the magnetic field generating component and the electric field generating component are simultaneously activated so that the magnetic field and the AC electric field cover the acoustic medium; High-frequency sound waves are generated by high-frequency acoustic transducers. The high-frequency sound waves pass through the acoustic medium, AC electric field, and magnetic field to cause nonlinear coupling between the sound waves and the fluid, thereby generating low-frequency sound waves.

[0013] Compared with the prior art, the present invention has the following beneficial technical effects: 1. The underwater millihertz seismic sound source transducer of the present invention can drive the fluid through electric and magnetic fields, so that the sound waves and the fluid are nonlinearly coupled, and can generate millihertz sound waves while maintaining a small volume, which can effectively meet the application requirements of prospecting, ultra-long-range detection, etc.; 2. The underwater millihertz seismic sound source transducer of the present invention can generate sound waves of 0.001 Hz to 10000 Hz in addition to millihertz sound waves, and can generate modulated sound waves by modulating high-frequency sound wave signals, magnetic fields and / or alternating electric fields. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0015] Figure 1 It is an axonometric diagram of an underwater millihertz seismic sound source transducer in an embodiment of the present invention; Figure 2is a cross-sectional view of an underwater millihertz seismic sound source transducer according to an embodiment of the present invention; Figure 3 1 is an exploded view of an underwater millihertz seismic sound source transducer in an embodiment of the present invention.

[0016] Reference numerals: high-frequency acoustic transducer 1 , magnetic field generating component 2 , electric field generating component 3 , acoustic rubber 4 , end shell 5 , outer shell 6 , inner frame 7 .

[0017] The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0018] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0019] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present invention are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0020] In addition, in the present invention, descriptions such as "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0021] In the present invention, unless otherwise clearly specified and limited, the terms "connection", "fixation", etc. should be understood in a broad sense. For example, "fixation" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection, a physical connection, or a wireless communication connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0022] In addition, the technical solutions between the various embodiments of the present invention can be combined with each other, but it must be based on the fact that ordinary technicians in the field can implement it. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0023] like Figures 1 to 3 The present embodiment shows an underwater millihertz seismic acoustic source transducer, which mainly includes a shell assembly, a high-frequency acoustic transducer 1, an acoustic medium, a magnetic field generating assembly 2, an electric field generating assembly 3 and an acoustic rubber 4, wherein a cavity is provided in the shell assembly. Specifically, the high-frequency acoustic transducer 1 is provided at the first end of the cavity for generating high-frequency acoustic waves; the acoustic rubber 4 is provided at the second end of the cavity for establishing an acoustic wave impedance matching condition; and the acoustic medium is provided between the high-frequency acoustic transducer 1 and the acoustic rubber 4. The magnetic field generating assembly 2 is provided on the shell assembly for generating a parallel magnetic field covering the acoustic medium; the electric field generating assembly 3 is provided on the shell assembly for generating an alternating electric field covering the acoustic medium, wherein the acoustic medium is an oscillating fluid. In the process of passing through the acoustic medium, the high-frequency acoustic transducer 1 drives the fluid as the acoustic medium through the magnetic field and the alternating electric field, so that the acoustic wave and the fluid are nonlinearly coupled, thereby being able to generate low-frequency acoustic waves while maintaining a small volume.

[0024] In this embodiment, the electric field generating component 3 includes two high-frequency electrodes, and two high-frequency motors are arranged on the left and right sides of the cavity. The magnetic field generating component 2 includes two magnets, and the two magnets are arranged on the upper and lower sides of the cavity, wherein the magnets can be strong magnetic magnets or electromagnets.

[0025] Specifically, the shell assembly includes an end shell 5, an outer shell 6 and an inner frame 7. The end shell 5 is a rectangular cover structure, and the outer shell 6 and the inner frame 7 are both rectangular cylindrical structures with openings at both ends. The end shell 5 is fixedly and sealedly connected to the first end of the outer shell 6 by bolts, sealing rings and other structures, and the high-frequency acoustic transducer 1 is arranged on the inner wall of the outer shell 6, and the acoustic rubber 4 is arranged at the second end of the outer shell 6. The inner frame 7 is embedded in the outer shell 6, and the opening of the first end of the inner frame 7 faces the high-frequency acoustic transducer 1, and the opening of the second end faces the acoustic rubber 4. Two high-frequency electrodes are respectively arranged on the side walls on the left and right sides of the inner frame 7, and two magnets are respectively fixed between the outer walls on the upper and lower sides of the inner frame 7 and the inner wall of the outer shell 6.

[0026] It is worth noting that in a specific application process, the outer shell 6 and the inner frame 7 are not limited to a rectangular cylindrical structure, but may also be a circular cylindrical, hexagonal cylindrical structure or the like.

[0027] In the specific implementation process, the inner walls on the left and right sides of the inner frame 7 are provided with card slots, and the two high-frequency electrodes are fixedly embedded in the card slots on the corresponding sides. At the same time, the side walls on the left and right sides of the inner frame 7 are provided with cable holes for leading out the cables of the high-frequency electrodes. In addition, the cross-section of the acoustic rubber 4 is a convex structure as a whole, and its convex part is sealed and embedded in the opening of the second end of the outer shell 6, and the remaining part abuts against the inner wall of the second end of the outer shell 6.

[0028] Based on the above underwater millihertz seismic sound source transducer, this embodiment also discloses a low-frequency sound wave generation method, which mainly includes the following steps: The liquid as the acoustic medium is encapsulated in the space to construct a liquid environment, the electric field generating component is connected to a high-frequency alternating current, such as 50kHz+0.01Hz, and the magnetic field generating component and the electric field generating component are started at the same time, so that the magnetic field and the alternating electric field cover the acoustic medium; High-frequency sound waves, such as 50kHz, are generated by a high-frequency acoustic transducer. The high-frequency sound waves pass through the acoustic medium, AC electric field, and magnetic field to cause nonlinear coupling between the sound waves and the fluid, thereby generating low-frequency sound waves, which eventually penetrate the acoustic rubber and radiate to the outside world.

[0029] The critical equilibrium condition for the nonlinear interaction between acoustic waves and flow structures is expressed as ,in is the interaction period, which depends on the incident sound frequency , expressed as . is the time required for the sound wave to propagate in the flow structure and is expressed as ,in , In wave turbulence theory, when the interaction time is much longer than the sound wave period (i.e. ), weak turbulence dominates. On the contrary, when Much shorter than (Right now ), strong nonlinear interactions occur, characterized by interactions with large-scale structures. The strong nonlinear interaction process transfers energy over a short distance and can facilitate the realization of seismic noise sources in a compact size. Based on this, this embodiment proposes a new low-frequency acoustic wave generation framework, which starts with the Euler equation and combines the forces from the electric field and the magnetic field, specifically:

[0030] in, is the fluid density, is the fluid velocity, is the fluid pressure, is the force due to the Lorentz force. is the body force at the angular frequency, is the fluid background density, is the i-direction coordinate, is the low frequency to be transmitted, For time, and They correspond to the physical quantities caused by the Lorentz force and acoustics, namely: is the fluid density caused by the Lorentz force, is the acoustically induced fluid density, is the fluid velocity caused by the Lorentz force, is the fluid velocity due to acoustics, is the fluid pressure caused by the Lorentz force, The fluid pressure caused by acoustics.

[0031] The nonlinear interaction between sound waves of different frequencies cannot produce high-amplitude ultra-low sound waves. In this embodiment, the Lorentz force is ignored. , and assumes is uniform, so the flow velocity caused by the Lorentz force can be approximated as . Then, we use Lighthill's acoustic analogy and Bern's approximation to analyze the nonlinear interaction between the sound wave and the driving fluid:

[0032] in, represents the particle velocity of the incident sound wave, represents the nonlinear interaction between the incident acoustic wave and the oscillating fluid. In this framework, the frequency is The incident sound wave Directional propagation, the sound pressure generated is defined as ,in is the wave number of the generated sound wave, then formula (2) can be simplified as:

[0033] in, is the incident sound wave intensity, the sound pressure generated by the nonlinear process exist It can be estimated as:

[0034] in, is the coordinate of the sound wave propagation direction; Equation (4) shows that the intensity of the generated sound wave increases with the increase of the intensity and frequency of the incident sound wave. It also clearly shows that the intensity of the induced sound wave is related to is inversely proportional, which means that as the frequency approaches zero ( ), the induced sound wave will reach a high amplitude. These characteristics all indicate that the scheme of inducing the generation of low-frequency sound waves by driving the oscillating fluid through parallel magnetic field and AC electric field, and nonlinear coupling of sound waves and fluid is feasible in this embodiment, and different from the traditional parameter array which requires a long integration distance, the method proposed in this embodiment can realize a compact millihertz sound source.

[0035] It is worth noting that the method in this embodiment can generate sound waves of 0.001 Hz to 10000 Hz in addition to millihertz sound waves, and can generate modulated sound waves by modulating high-frequency sound wave signals, magnetic fields and / or AC electric fields.

[0036] The above description is only a preferred embodiment of the present invention, and does not limit the patent scope of the present invention. All equivalent structural changes made by using the contents of the present invention specification and drawings under the inventive concept of the present invention, or directly / indirectly applied in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. An underwater millihertz seismic acoustic source transducer, characterized in that: It comprises a shell component, a high-frequency acoustic transducer, an acoustic medium, a magnetic field generating component, an electric field generating component and an acoustic rubber, wherein a cavity is provided in the shell component; The high-frequency acoustic transducer is arranged at a first end of the cavity, the acoustic rubber is arranged at a second end of the cavity, and the acoustic medium is arranged between the high-frequency acoustic transducer and the acoustic rubber; The magnetic field generating assembly is arranged on the shell assembly and is used to generate a magnetic field covering the acoustic medium; The electric field generating component is arranged on the shell component, and is used to generate an alternating electric field covering the acoustic medium; The acoustic medium is an oscillating fluid.

2. The underwater millihertz seismic sound source transducer according to claim 1, characterized in that: The electric field generating assembly includes two high-frequency electrodes, and the two high-frequency motors are arranged on the left and right sides of the cavity; The magnetic field generating assembly comprises two magnets, and the two magnets are arranged on the upper and lower sides of the cavity.

3. The underwater millihertz seismic sound source transducer according to claim 2, characterized in that: The magnet is a strong magnet or an electromagnet.

4. The underwater millihertz seismic sound source transducer according to claim 2 or 3, characterized in that: The housing assembly comprises an end housing, an outer housing and an inner frame; The outer shell and the inner frame are both rectangular cylindrical structures with openings at both ends, the end shell is arranged at the first end of the outer shell, the acoustic rubber is arranged at the second end of the outer shell, and the high-frequency acoustic transducer is arranged on the inner wall of the outer shell; The inner frame is embedded in the outer shell, and the opening of the first end of the inner frame faces the high-frequency acoustic transducer, and the opening of the second end faces the acoustic rubber; The two high-frequency electrodes are respectively arranged on the side walls of the left and right sides of the inner frame, and the two magnets are respectively arranged between the outer walls of the upper and lower sides of the inner frame and the inner wall of the outer shell.

5. The underwater millihertz seismic sound source transducer according to claim 4, characterized in that: The cross section of the acoustic rubber is a convex structure as a whole, the convex part of which is sealed and embedded in the opening of the second end of the outer shell, and the remaining part abuts against the inner wall of the second end of the outer shell.

6. The underwater millihertz seismic sound source transducer according to claim 2 or 3, characterized in that: The inner walls on the left and right sides of the inner frame are provided with card slots, and the two high-frequency electrodes are fixedly embedded in the card slots on the corresponding sides, and the side walls on the left and right sides of the inner frame are provided with cable holes.

7. A method for generating low-frequency sound waves, characterized in that: An underwater millihertz seismic sound source transducer as claimed in any one of claims 1 to 6; The low-frequency sound wave generation method comprises the following steps: After encapsulating the acoustic medium in the space, the magnetic field generating component and the electric field generating component are simultaneously activated so that the magnetic field and the AC electric field cover the acoustic medium; High-frequency sound waves are generated by high-frequency acoustic transducers. The high-frequency sound waves pass through the acoustic medium, AC electric field, and magnetic field to cause nonlinear coupling between the sound waves and the fluid, thereby generating low-frequency sound waves.

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