Method for measuring volume velocity of unknown sound source in complex environment

Abstract

The invention provides a method for measuring the volume velocity of an unknown sound source in a complex environment, and belongs to the field of equivalent monopole sound source testing. Putting a self-made electromagnetic sound source into a test water area; building a hydrophone array; direct sound pressure at each hydrophone position is calculated, and a reference sound pressure matrix is formed; establishing a relational expression among the holographic surface sound pressure vector of any sound source, the volume velocity vector of any sound source and the Green function; establishing a relational expression between the holographic surface sound pressure vector of any sound source and the source intensity of each equivalent source; establishing an equation for solving the volume velocity vector of any sound source; extracting direct sound pressure; establishing an optimization objective function, and obtaining an optimal equivalent source position matrix r; obtaining a final Green function; replacing the unknown sound source with a to-be-measured unknown sound source to realize the measurement of the volume velocity vector of the unknown sound source; according to the method, reverberation interference can be effectively stripped, a reliable correction method is provided for acoustic reciprocity testing in a complex reverberation environment, and the volume velocity of an unknown sound source is measured.

Description

Technical Field

[0001] This invention belongs to the field of equivalent monopole sound source testing, and mainly relates to a method for measuring the volume velocity of an unknown sound source in a complex environment. Background Technology

[0002] The reciprocity principle has significant application value in underwater acoustic testing. When measuring the acoustic radiation characteristics of underwater structures based on the reciprocity principle, accurate quantification of the sound source volume velocity is crucial for ensuring test reliability. Conventional methods acquire sound pressure data using a hydrophone array deployed around the sound source and derive the volume velocity through inversion calculations based on the free-field assumption. However, the reverberation effect caused by complex boundary conditions in the underwater environment can lead to significant deviations in the measurement results. Literature studies show that the transfer functions obtained by direct measurement methods and reciprocity derivation methods exhibit good consistency in spectral trends, but the amplitude difference can reach 5 dB. This phenomenon is directly attributed to the inaccuracy of volume velocity calculation during the reciprocity test. Therefore, establishing an effective volume velocity correction method in underwater scenarios with significant reverberation interference is a pressing technical challenge that needs to be addressed in this field, and currently, there is no effective solution. Summary of the Invention

[0003] The main purpose of this invention is to solve the problem of reverberation interference in the measurement of sound source volume velocity in actual waters. It proposes a method for measuring the volume velocity of unknown sound sources in complex environments, which can effectively remove reverberation interference, accurately restore the direct sound propagation characteristics, provide a reliable correction method for acoustic reciprocity testing in complex reverberation environments, and realize the measurement of the volume velocity of unknown sound sources.

[0004] This invention designs a method for measuring the volume velocity of an unknown sound source in complex environments, solving the technical challenge of establishing an effective volume velocity correction method in underwater scenarios with significant reverberation interference.

[0005] A method for measuring the volume velocity of an unknown sound source in a complex environment includes the following steps: Step 1: Establish a test water area with stable hydrological conditions; install an accelerometer on a self-made electromagnetic sound source; place the self-made electromagnetic sound source into the test water area; Step 2: Construct a hydrophone array in the test water area; the hydrophone array consists of M units; M is a positive integer not less than 9. Step 3: Since it is a homemade electromagnetic sound source, the volume and velocity of the homemade electromagnetic sound source... Q 0 is known; based on the coordinates of each hydrophone in the hydrophone array in step two, and according to the volume velocity of the self-made electromagnetic sound source... Q The relationship between 0 and direct sound pressure is used to calculate the direct sound pressure at each hydrophone location. M direct sound pressure levels corresponding to M hydrophones Forming a reference sound pressure matrix ; Step 4: Set the holographic surface sound pressure vector of any sound source as... ; Let the volume velocity vector of any sound source be... ; Set the Green's function as ;Establish , , Relationship: ; Step 5: In a test water area with stable hydrological conditions, there exists an equivalent source relative to the self-made electromagnetic sound source; the number of equivalent sources is set to N, and the source strength of each equivalent source is... ; The sequence number of the equivalent source; It is an N*1 order vector; based on the Green's function Establish and Relationship: ;in, For the first The source strength of an equivalent source; It is a Green's function based on the equivalent source location; Step 6: Apply the Green's function Perform singular value decomposition; and based on the singular value decomposition results, proceed from step four. , , The relation is established under the condition of no regularization, using and Solve for the volume velocity vector of an arbitrary sound source. The equation; Step 7: Under regularization conditions, solve for the volume velocity vector of any sound source. The equation; Step 8: Based on the coordinates, obtain the volume velocity vector of any sound source from Step 7. Extract the direct sound pressure at the measurement location from the equation. ; Step 9: Based on the reference sound pressure matrix in Step 3 and the direct sound pressure in step eight The particle swarm optimization algorithm is used to establish the optimization objective function; the layout of the optimization source is optimized by iteratively updating the particle position and velocity. Each particle corresponds to a potential equivalent source configuration, thereby obtaining the optimal equivalent source position matrix r. Step 10: Substitute the optimal equivalent source location matrix r into Step 5 to obtain the Green's function under the test water environment. ; Step 11: Replace the self-made electromagnetic sound source with the unknown sound source to be tested and place it in the same location in the test water area; in the same environment, the Green's function... Unchanged; the holographic sound pressure vector of the unknown sound source radiation obtained by measuring the hydrophone array built in step two is: Combined with the Green's function obtained in step ten Substituting the regularization conditions from step seven, the volume velocity vector of any sound source... Solving the equations allows us to measure the volume velocity vector of an unknown sound source.

[0006] In the above-mentioned method for measuring the volume velocity of an unknown sound source in a complex environment, in step one, the frequency of the self-made electromagnetic sound source is 10-3kHz, the diameter of the radiating surface is 0.2m, and the maximum vibration velocity is 0.5m / s. The hydrological conditions of the test water area are as follows: The test area is a closed or semi-closed water body, with still water or a flow velocity of less than 0.1 m / s; the temperature difference between the surface and deep water layers is less than 1℃ at night; the test area is a salinity stable zone to reduce the impact of sound velocity gradient on sound propagation; The homemade electromagnetic sound source was suspended at a position between 1 / 3 and 1 / 2 of the water depth in the test area.

[0007] In the above-mentioned method for measuring the volume velocity of an unknown sound source in a complex environment, the accelerometer is installed at the center of the vibration surface of a self-made electromagnetic sound source or at the radial 1 / 4 position, and is coupled with beeswax.

[0008] In the above-mentioned method for measuring the volume velocity of an unknown sound source in a complex environment, in step two, M=13; the 13 hydrophones are labeled as 1-13; Set the coordinate position of the homemade electromagnetic sound source as the origin (0,0,0,), and establish a coordinate system (x,y,z); where the positive x-axis is the horizontal emission direction of the homemade electromagnetic sound source; the positive z-axis is vertically upward; and the y-axis is determined by the right-hand rule; then the coordinates of the 13 hydrophones are as follows: The coordinates of hydrophone No. 1 are (1.63m, -0.75m, -0.97m). The coordinates of hydrophone No. 2 are (1.63m, 0m, -0.97m). The coordinates of hydrophone No. 3 are (1.63m, 0.75m, -0.97m). The coordinates of hydrophone No. 4 are (1.63m, -0.75m, -0.22m). The coordinates of hydrophone No. 5 are (1.85m, 0m, 0m); The coordinates of hydrophone No. 6 are (1.63m, 0.75m, -0.22m). The coordinates of hydrophone No. 7 are (1.63m, -0.75m, 0.53m). The coordinates of hydrophone No. 8 are (1.63m, 0m, 0.53m). The coordinates of hydrophone No. 9 are (1.63m, 0.75m, 0.53m). The coordinates of hydrophone No. 10 are (0.85m, 0m, 0m). The coordinates of hydrophone No. 11 are (0.09m, 0.8m, 0m). The coordinates of hydrophone No. 12 are (0.09m, 0m, 0m). The coordinates of hydrophone No. 13 are (0.09m, -0.8m, 0m).

[0009] In the above-mentioned method for measuring the volume velocity of an unknown sound source in a complex environment, the accuracy of the measurement was verified using a No. 12 hydrophone and an accelerometer. The specific method is as follows: Volume velocity of a homemade electromagnetic sound source measured by an accelerometer for:

[0010] In the formula, The vibration surface area of ​​the self-made electromagnetic sound source; The imaginary unit; Angular frequency; These are accelerometer measurements; Volume velocity of the homemade electromagnetic sound source measured using hydrophone No. 12 for:

[0011] In the formula, The distance between the hydrophone and the center of the sound source; For frequency; The density of the medium; The sound pressure measured by hydrophone No. 12; contrast Q 0v and Q 0p ,when Q 0v and Q 0p If the values ​​are equal, the volume velocity of the homemade electromagnetic sound source is determined to be accurate; otherwise, adjust the position of hydrophone #12 until... Q 0v and Q 0p Thus, the true value of the sound source volume velocity is obtained.

[0012] In the above-described method for measuring the volume velocity of an unknown sound source in a complex environment, step three involves using the volume velocity of a self-made electromagnetic sound source. Q 0. Calculate the direct sound pressure measured by each hydrophone. The method is as follows:

[0013] In the formula, For the first i The position of the hydrophone from the sound source.

[0014] In the above-mentioned method for measuring the volume velocity of an unknown sound source in a complex environment, in step five, there is a boundary reflecting surface in a closed or semi-closed water area to reflect the self-made electromagnetic sound source. The N equivalent sources of the electromagnetic sound source are located on the boundary reflecting surface. For any sound source, the sound field formed by its outward radiation is accurately fitted by the linear superposition of the sound fields radiated by the equivalent sources.

[0015] In the above-described method for measuring the volume velocity of an unknown sound source under complex conditions, step six involves the Green's function... The method for performing singular value decomposition is as follows:

[0016] In the formula, It is a diagonal matrix; The diagonal elements are singular values. , ; and It is a unitary matrix whose column vectors are mutually orthogonal; It is the conjugate transpose; Solve for the volume velocity vector of an arbitrary sound source under unregularized conditions. The equation is: ,

[0017] In the formula, Green's function matrix G The reverse.

[0018] In the aforementioned method for measuring the volume velocity of an unknown sound source under complex conditions, step seven involves solving for the volume velocity vector of any sound source under regularization conditions. The method for using equations is as follows: Introducing Tikhonov regularization, let the absolute error be... To minimize the error e, Tikhonov introduced a penalty function. When the first derivative of J with respect to Q is zero, the error e has a minimum value, then we can obtain... Q for:

[0019] In the formula, I For unit array; For regularization parameters; Regularization parameters are selected using the generalized cross-validation method gcv(*). :

[0020] Obtain the volume velocity vector of any sound source under regularization conditions. The equation: .

[0021] In the above-described method for measuring the volume velocity of an unknown sound source under complex conditions, the objective function in step nine is: .

[0022] Compared with the prior art, the present invention has the following advantages: (1) The present invention constructs a test water area with stable hydrological conditions, selects closed or semi-closed water areas (such as small bays, deep water areas of lakes), avoids medium disturbance caused by water flow, waves or tides, and at the same time ensures that the vertical stratification effect of water temperature is weak and the salinity change is negligible during the test period, reduces the influence of sound velocity gradient on sound propagation, and ensures the accuracy of measurement. (2) The present invention sets the self-made sound source at a depth of 1 / 3 to 1 / 2 of the water to avoid surface / bottom reflection interference as much as possible; at the same time, the radius or spacing of the hydrophone array is built in a suitable position to satisfy the spatial sampling theorem, so as to realize the accurate measurement of the self-made sound source and provide a guarantee for the determination of the equivalent source position; (3) This invention establishes the relationship between the holographic surface sound pressure vector of any sound source, the volume velocity vector of any sound source, and the Green's function; establishes the relationship between the holographic surface sound pressure vector of any sound source and the source intensity of each equivalent source; establishes the equation for solving the volume velocity vector of any sound source; extracts the direct sound pressure; establishes the optimization objective function to obtain the optimal equivalent source position matrix r; obtains the final Green's function; replaces the unknown sound source to be tested to realize the measurement of the volume velocity vector of the unknown sound source; this invention can effectively remove reverberation interference, provides a reliable correction method for acoustic reciprocity testing in complex reverberation environments, and realizes the measurement of the volume velocity of the unknown sound source. Attached Figure Description

[0023] Figure 1 This is a flowchart illustrating the measurement process of the volume velocity of an unknown sound source under complex conditions according to the present invention. Figure 2This is a schematic diagram showing the relative positions of each hydrophone and the self-made electromagnetic sound source in this invention; Figure 3 This is a schematic diagram of the equivalent source location of the present invention; Figure 4 This is a flowchart of the particle swarm optimization algorithm of the present invention. Detailed Implementation

[0024] The technical solutions of this application will be clearly and completely described below with reference to the accompanying drawings of the embodiments. The embodiments described are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0025] The volumetric velocity Q of a sound source is defined as the volume of medium passing through a reference surface per unit time. It reflects the ability of the sound source to push or pull into the surrounding medium when it vibrates, and is mathematically expressed as the product of the effective vibration area A of the sound source and the vibration velocity v.

[0026]

[0027] The SI unit for volumetric velocity is cubic meters per second (m). 3 / s), with expression The units are consistent.

[0028] Methods for measuring the volume velocity of unknown sound sources in complex environments, such as... Figure 1 As shown, the specific steps include the following: Step 1: Establish a test water area with stable hydrological conditions; install an accelerometer on a self-made electromagnetic sound source; place the self-made electromagnetic sound source into the test water area.

[0029] The self-made electromagnetic sound source has a frequency of 10-3kHz, a radiating surface diameter of 0.2m, and a maximum vibration velocity of 0.5m / s.

[0030] This invention selects an electromagnetic sound source characterized by low frequency, high linearity, high power, and omnidirectional properties. Frequency range: 10 Hz-3 kHz; radiating surface diameter: 0.2 m (plane vibration); maximum vibration velocity: 0.5 m / s. Sound can be heard and the radiating surface vibration observed when excited in air with a small current signal. The electromagnetic sound source should not be tested with a large signal in air (a signal of approximately 3A can be used for testing). Overloading is prohibited during use; the applied current must not exceed the safe operating voltage (10A RMS value, short pulse), otherwise, functional components may be easily burned out, leading to transducer damage.

[0031] The hydrological conditions of the test water area are as follows: The test area was a closed or semi-closed body of water, with still water or a flow velocity of less than 0.1 m / s; the temperature difference between the surface and deep layers of the water was less than 1℃ at night; the test area was a salinity stable zone to reduce the influence of the sound velocity gradient on sound propagation. A self-made electromagnetic sound source was suspended at 1 / 3 to 1 / 2 of the water depth in the test area.

[0032] The accelerometer is installed at the center of the vibration surface of the self-made electromagnetic sound source or at the radial 1 / 4 position, and is coupled with beeswax.

[0033] Step 2: Construct a hydrophone array in the test water area. The hydrophone array consists of M units; M is a positive integer not less than 9.

[0034] In this embodiment, M=13; the 13 hydrophones are numbered 1-13.

[0035] Set the coordinate position of the self-made electromagnetic sound source as the origin (0,0,0,), and establish a coordinate system (x,y,z); where the positive x-axis is the horizontal emission direction of the self-made electromagnetic sound source; the positive z-axis is vertically upward; and the y-axis is determined by the right-hand rule.

[0036] The test area was located inside a bay with stable hydrological conditions. The water depth was approximately 60 meters, ranging from 30 to 500 meters from the shore. The test equipment was placed 20 meters underwater. The test was conducted at night when background noise levels were low, which was beneficial for data acquisition and met the signal-to-noise ratio requirements. An array of 13 hydrophones was positioned directly in front of the sound source. The coordinates of the 13 hydrophones are as follows: The coordinates of hydrophone #1 are (1.63m, -0.75m, -0.97m); the coordinates of hydrophone #2 are (1.63m, 0m, -0.97m); the coordinates of hydrophone #3 are (1.63m, 0.75m, -0.97m); the coordinates of hydrophone #4 are (1.63m, -0.75m, -0.22m); the coordinates of hydrophone #5 are (1.85m, 0m, 0m); the coordinates of hydrophone #6 are (1.63m, 0.75m, -0.22m); the coordinates of hydrophone #7 are... The coordinates of the following hydrophones are: (1.63m, -0.75m, 0.53m); (1.63m, 0m, 0.53m); (1.63m, 0.75m, 0.53m); (0.85m, 0m, 0m); (0.09m, 0.8m, 0m); (0.09m, 0m, 0m); (0.09m, 0m, 0m); (0.09m, -0.8m, 0m).

[0037] The relative positions of each hydrophone and the homemade electromagnetic sound source are as follows: Figure 2 As shown.

[0038] During testing, the accuracy of the measurements was verified using a No. 12 hydrophone and an accelerometer. The specific method was as follows: Volume velocity of a homemade electromagnetic sound source measured by an accelerometer for:

[0039] In the formula, The vibration surface area of ​​the self-made electromagnetic sound source;

[0040] It is the imaginary unit.

[0041] ω is the angular frequency.

[0042] These are accelerometer measurements.

[0043] Volume velocity of the homemade electromagnetic sound source measured using hydrophone No. 12 for:

[0044] In the formula, The distance between the hydrophone and the center of the sound source.

[0045] For frequency.

[0046] The density is the medium.

[0047] The sound pressure measured by hydrophone No. 12; contrast Q 0v and Q 0p ,when Q 0v and Q 0p If the values ​​are equal, the volume velocity of the homemade electromagnetic sound source is determined to be accurate; otherwise, adjust the position of hydrophone #12 until... Q 0v and Q 0p Thus, the true value of the sound source volume velocity is obtained.

[0048] Step 3: Since it is a homemade electromagnetic sound source, the volume and velocity of the homemade electromagnetic sound source... Q 0 is known; based on the coordinates of each hydrophone in the hydrophone array in step two, and according to the volume velocity of the self-made electromagnetic sound source... Q The relationship between 0 and direct sound pressure is used to calculate the direct sound pressure at each hydrophone location. M direct sound pressure levels corresponding to M hydrophones Forming a reference sound pressure matrix .

[0049] Sound pressure: The instantaneous pressure change caused by sound waves in a medium (such as water), a direct measure of sound wave vibration. The unit is Pascal (Pa), representing the difference between local pressure and static pressure. Sound pressure varies with time and is usually expressed as the effective value (RMS) or peak value.

[0050] Total sound pressure level: The total pressure of all sound waves superimposed at the receiving point, including contributions from direct sound and reverberation.

[0051] Direct sound: The path by which sound waves travel directly from the sound source to the receiving point without reflection.

[0052] Reverberation: The continuous sound field formed after sound waves are reflected multiple times by boundaries (water surface, bottom, obstacles).

[0053] Free-field sound pressure: In an open space without reflection boundaries, the sound pressure directly radiated by a sound source satisfies the propagation laws of spherical waves or plane waves.

[0054] Based on the volume velocity of the self-made electromagnetic sound source Q 0. Calculate the direct sound pressure measured by each hydrophone. The method is as follows:

[0055] In the formula, For the first i The position of the hydrophone from the sound source.

[0056] Step 4: Set the holographic surface sound pressure vector of any sound source as... ; Let the volume velocity vector of any sound source be... ; Set the Green's function as ;Establish , , Relationship: .

[0057] Step 5: In a test water area with stable hydrological conditions, there exists an equivalent source relative to the self-made electromagnetic sound source; the number of equivalent sources is set to N, and the source strength of each equivalent source is... ; The sequence number of the equivalent source; It is an N*1 order vector; based on the Green's function Establish and Relationship: ;in, For the first The source strength of an equivalent source; It is a Green's function based on the equivalent source location.

[0058] In enclosed or semi-enclosed water bodies, boundary reflective surfaces exist to reflect a self-made electromagnetic sound source. N equivalent sources of the electromagnetic sound source are located on these boundary reflective surfaces. For any sound source, the sound field radiated outwards is accurately fitted by the linear superposition of the sound fields radiated by the equivalent sources. A schematic diagram of the equivalent source locations is shown below. Figure 3 As shown.

[0059] Step 6: Apply the Green's function Perform singular value decomposition; and based on the singular value decomposition results, proceed from step four. , , The relation is established under the condition of no regularization, using and Solve for the volume velocity vector of an arbitrary sound source. The equation.

[0060] Green's function The method for performing singular value decomposition is as follows:

[0061] In the formula, It is a diagonal matrix; The diagonal elements are singular values. , ; and It is a unitary matrix whose column vectors are mutually orthogonal; It is the conjugate transpose; Solve for the volume velocity vector of an arbitrary sound source under unregularized conditions. The equation is: ,

[0062] In the formula, Green's function matrix G The reverse.

[0063] Step 7: Under regularization conditions, solve for the volume velocity vector of any sound source. The equation.

[0064] Solving for the volume velocity vector of an arbitrary sound source under regularization conditions. The method for using equations is as follows: Introducing Tikhonov regularization, let the absolute error be... To minimize the error e, Tikhonov introduced a penalty function. When the first derivative of J with respect to Q is zero, the error e has a minimum value, then we can obtain... Q for:

[0065] In the formula, I For unit array; For regularization parameters; Regularization parameters are selected using the generalized cross-validation method gcv(*). :

[0066] Obtain the volume velocity vector of any sound source under regularization conditions. The equation: .

[0067] Step 8: Based on the coordinates, obtain the volume velocity vector of any sound source from Step 7. Extract the direct sound pressure at the measurement location from the equation. .

[0068] Step 9: Based on the reference sound pressure matrix in Step 3 and the direct sound pressure in step eight The particle swarm optimization algorithm is used to establish the objective function; the layout of the source is optimized by iteratively updating the particle position and velocity. Each particle corresponds to a potential equivalent source configuration, thereby obtaining the optimal equivalent source position matrix r.

[0069] The objective function to be optimized is: .

[0070] like Figure 4 As shown, each particle represents a potential equivalent source configuration, and its solution consists of three main parts: the magnitude (A) of the source, the phase (A), and the phase (B). The source's location is described by three variables: x, y, and z, representing its coordinates in three-dimensional space. During optimization, the particle swarm optimization (PSO) algorithm continuously adjusts the position and velocity of particles to optimize the source's arrangement. The dimensions of the search space vary depending on the specific problem. Typically, particles search throughout the entire volume of the object to find the optimal source configuration. The PSO method allows for searching across multiple degrees of freedom, automatically identifying the source locations that yield the best results from equivalent source methods.

[0071] Particle swarm optimization (PSO) continuously explores and optimizes the location of sources by adjusting the velocity and position of particles, gradually approaching the global optimum. Each particle's position update is influenced not only by its own historical experience but also by the experience of the entire particle swarm, ensuring the globality and efficiency of the search process. Ultimately, through the collaborative work of the particle swarm, the global optimum of source placement can be achieved, thereby improving the computational accuracy and stability of the equivalent source method in acoustic problems.

[0072] Step 10: Substitute the optimal equivalent source location matrix r into Step 5 to obtain the Green's function under the test water environment. .

[0073] Step 11: Replace the self-made electromagnetic sound source with the unknown sound source to be tested and place it in the same location in the test water area; in the same environment, the Green's function... Unchanged; the holographic sound pressure vector of the unknown sound source radiation obtained by measuring the hydrophone array built in step two is: Combined with the Green's function obtained in step ten Substituting the regularization conditions from step seven, the volume velocity vector of any sound source... Solving the equations allows us to measure the volume velocity vector of an unknown sound source.

[0074] The present invention constructs a test water area with stable hydrological conditions, selecting closed or semi-closed water areas (such as small bays, deep water areas of lakes) to avoid medium disturbance caused by water flow, waves or tides. At the same time, it ensures that the vertical stratification effect of water temperature is weak and the salinity change is negligible during the test period, reduces the influence of sound velocity gradient on sound propagation, and ensures the accuracy of measurement.

[0075] This invention places a self-made sound source at a depth of 1 / 3 to 1 / 2 of the water surface to minimize surface / bottom reflection interference; at the same time, a hydrophone array is built in a suitable location with a radius or spacing that satisfies the spatial sampling theorem, enabling accurate measurement of the self-made sound source and providing a guarantee for determining the location of the equivalent source.

[0076] This invention establishes the relationship between the holographic surface sound pressure vector of any sound source, the volume velocity vector of any sound source, and the Green's function; establishes the relationship between the holographic surface sound pressure vector of any sound source and the source intensity of each equivalent source; establishes the equation for solving the volume velocity vector of any sound source; extracts the direct sound pressure; establishes an optimization objective function to obtain the optimal equivalent source position matrix r; obtains the final Green's function; replaces the unknown sound source to be measured, and realizes the measurement of the volume velocity vector of the unknown sound source; this invention can effectively remove reverberation interference, provides a reliable correction method for acoustic reciprocity testing in complex reverberation environments, and realizes the measurement of the volume velocity of unknown sound sources.

[0077] The above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application.

Claims

1. A method for measuring the volume velocity of an unknown sound source in a complex environment, characterized in that: Includes the following steps: Step 1: Establish a test water area with stable hydrological conditions; install an accelerometer on a self-made electromagnetic sound source; place the self-made electromagnetic sound source into the test water area; Step 2: Construct a hydrophone array in the test water area; the hydrophone array consists of M units; M is a positive integer not less than 9. Step 3: Since it is a homemade electromagnetic sound source, the volume and velocity of the homemade electromagnetic sound source... Q 0 is known; based on the coordinates of each hydrophone in the hydrophone array in step two, and according to the volume velocity of the self-made electromagnetic sound source... Q The relationship between 0 and direct sound pressure is used to calculate the direct sound pressure at each hydrophone location. M direct sound pressure levels corresponding to M hydrophones Forming a reference sound pressure matrix ; Step 4: Set the holographic surface sound pressure vector of any sound source as... ; Let the volume velocity vector of any sound source be... ; Set the Green's function as ;Establish , , Relationship: ; Step 5: In a test water area with stable hydrological conditions, there exists an equivalent source relative to the self-made electromagnetic sound source; the number of equivalent sources is set to N, and the source strength of each equivalent source is... ; The sequence number of the equivalent source; It is an N*1 order vector; based on the Green's function Establish and Relationship: ;in, For the first The source strength of an equivalent source; It is a Green's function based on the equivalent source location; Step 6: Apply the Green's function Perform singular value decomposition; and based on the singular value decomposition results, proceed from step four. , , The relation is established under the condition of no regularization, using and Solve for the volume velocity vector of an arbitrary sound source. The equation; Step 7: Under regularization conditions, solve for the volume velocity vector of any sound source. The equation; Step 8: Based on the coordinates, obtain the volume velocity vector of any sound source from Step 7. Extract the direct sound pressure at the measurement location from the equation. ; Step 9: Based on the reference sound pressure matrix in Step 3 and the direct sound pressure in step eight The particle swarm optimization algorithm is used to establish the optimization objective function; the layout of the optimization source is optimized by iteratively updating the particle position and velocity. Each particle corresponds to a potential equivalent source configuration, thereby obtaining the optimal equivalent source position matrix r. Step 10: Substitute the optimal equivalent source location matrix r into Step 5 to obtain the Green's function under the test water environment. ; Step 11: Replace the self-made electromagnetic sound source with the unknown sound source to be tested and place it in the same location in the test water area; in the same environment, the Green's function... Unchanged; the holographic sound pressure vector of the unknown sound source radiation obtained by measuring the hydrophone array built in step two is: Combined with the Green's function obtained in step ten Substituting the regularization conditions from step seven, the volume velocity vector of any sound source... Solving the equations allows us to measure the volume velocity vector of an unknown sound source.

2. The method for measuring the volume velocity of an unknown sound source in a complex environment according to claim 1, characterized in that: In step one, the frequency of the self-made electromagnetic sound source is 10-3kHz, the diameter of the radiating surface is 0.2m, and the maximum vibration velocity is 0.5m / s. The hydrological conditions of the test water area are as follows: The test area is a closed or semi-closed water body, with still water or a flow velocity of less than 0.1 m / s; the temperature difference between the surface and deep water layers is less than 1℃ at night; the test area is a salinity stable zone to reduce the impact of sound velocity gradient on sound propagation; The homemade electromagnetic sound source was suspended at a position between 1 / 3 and 1 / 2 of the water depth in the test area.

3. The method for measuring the volume velocity of an unknown sound source in a complex environment according to claim 1, characterized in that: The accelerometer is installed at the center of the vibration surface of the self-made electromagnetic sound source or at the radial 1 / 4 position, and is coupled with beeswax.

4. The method for measuring the volume velocity of an unknown sound source in a complex environment according to claim 1, characterized in that: In step two, M=13; the 13 hydrophones are numbered 1-13. Set the coordinate position of the homemade electromagnetic sound source as the origin (0,0,0,), and establish a coordinate system (x,y,z); where the positive x-axis is the horizontal emission direction of the homemade electromagnetic sound source; the positive z-axis is vertically upward; and the y-axis is determined by the right-hand rule; then the coordinates of the 13 hydrophones are as follows: The coordinates of hydrophone No. 1 are (1.63m, -0.75m, -0.97m). The coordinates of hydrophone No. 2 are (1.63m, 0m, -0.97m). The coordinates of hydrophone No. 3 are (1.63m, 0.75m, -0.97m). The coordinates of hydrophone No. 4 are (1.63m, -0.75m, -0.22m). The coordinates of hydrophone No. 5 are (1.85m, 0m, 0m); The coordinates of hydrophone No. 6 are (1.63m, 0.75m, -0.22m). The coordinates of hydrophone No. 7 are (1.63m, -0.75m, 0.53m). The coordinates of hydrophone No. 8 are (1.63m, 0m, 0.53m). The coordinates of hydrophone No. 9 are (1.63m, 0.75m, 0.53m). The coordinates of hydrophone No. 10 are (0.85m, 0m, 0m). The coordinates of hydrophone No. 11 are (0.09m, 0.8m, 0m). The coordinates of hydrophone No. 12 are (0.09m, 0m, 0m). The coordinates of hydrophone No. 13 are (0.09m, -0.8m, 0m).

5. The method for measuring the volume velocity of an unknown sound source in a complex environment according to claim 4, characterized in that: During testing, the accuracy of the measurements was verified using a No. 12 hydrophone and an accelerometer. The specific method was as follows: Volume velocity of a homemade electromagnetic sound source measured by an accelerometer for: In the formula, The vibration surface area of ​​the self-made electromagnetic sound source; The imaginary unit; Angular frequency; These are accelerometer measurements; Volume velocity of the homemade electromagnetic sound source measured using hydrophone No. 12 for: In the formula, The distance between the hydrophone and the center of the sound source; For frequency; The density of the medium; The sound pressure measured by hydrophone No. 12; contrast Q 0v and Q 0p ,when Q 0v and Q 0p If the values ​​are equal, the volume velocity of the homemade electromagnetic sound source is determined to be accurate; otherwise, adjust the position of hydrophone #12 until... Q 0v and Q 0p Thus, the true value of the sound source volume velocity is obtained.

6. The method for measuring the volume velocity of an unknown sound source in a complex environment according to claim 5, characterized in that: In step three, based on the volume velocity of the self-made electromagnetic sound source... Q 0. Calculate the direct sound pressure measured by each hydrophone. The method is as follows: In the formula, For the first i The position of the hydrophone from the sound source.

7. The method for measuring the volume velocity of an unknown sound source in a complex environment according to claim 6, characterized in that: In step five, there is a boundary reflective surface in the closed or semi-closed water area to reflect the self-made electromagnetic sound source. The N equivalent sources of the electromagnetic sound source are located on the boundary reflective surface. For any sound source, the sound field formed by its outward radiation is accurately fitted by the linear superposition of the sound fields radiated by the equivalent sources.

8. The method for measuring the volume velocity of an unknown sound source in a complex environment according to claim 7, characterized in that: In step six, the Green's function is... The method for performing singular value decomposition is as follows: In the formula, It is a diagonal matrix; The diagonal elements are singular values. , ; and It is a unitary matrix whose column vectors are mutually orthogonal; It is the conjugate transpose; Solve for the volume velocity vector of an arbitrary sound source under unregularized conditions. The equation is: ， In the formula, Green's function matrix G The reverse.

9. The method for measuring the volume velocity of an unknown sound source in a complex environment according to claim 8, characterized in that: In step seven, under regularization conditions, the volume velocity vector of any sound source is solved. The method for using equations is as follows: Introducing Tikhonov regularization, let the absolute error be... To minimize the error e, Tikhonov introduced a penalty function. ; When the first derivative of J with respect to Q is zero, the error e has a minimum value, then we can obtain... Q for: In the formula, I For unit array; For regularization parameters; Regularization parameters are selected using the generalized cross-validation method gcv(*). : Obtain the volume velocity vector of any sound source under regularization conditions. The equation: 。 10. The method for measuring the volume velocity of an unknown sound source in a complex environment according to claim 8, characterized in that: In step nine, the objective function to be optimized is: 。

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