A method, system and storage medium for predicting three-dimensional structural sound field in shallow water channels

Abstract

The invention discloses a method, system and storage medium for predicting three-dimensional structural sound field under a shallow sea channel, and relates to the technical field of shallow sea environment sound radiation. The method comprises the following steps: setting a point sound source and a surface sound source inside a structural sound source as equivalent sources of the structural sound source; obtaining the strength of each equivalent source based on the surface velocity of the structural sound source and the Green's function of the equivalent source; establishing a sound radiation model using a multi-physics field coupling FEM method; analyzing the directivity of the sound radiation based on the sound radiation model to obtain the far-field distance of the sound radiation of the structural sound source; for the near-field area, obtaining the sound radiation characteristics using the sound radiation model, and for the far-field area, calculating the far-field sound radiation characteristics using the parabolic equation method in a step-by-step manner. The invention combines an equivalent point sound source and an equivalent surface sound source as equivalent sources of the structural sound source, establishes a sound radiation model using the FEM method to calculate the sound radiation characteristics of the near-field area, and uses the parabolic equation method to calculate the far-field sound radiation characteristics, thereby improving the calculation accuracy of the model and ensuring the accuracy of the sound field calculation.

Description

Technical Field

[0001] The present invention relates to the technical field of shallow sea environment sound radiation, and more specifically to a method, system and storage medium for predicting three-dimensional structural sound field in a shallow sea channel. Background Art

[0002] Studying the radiated sound field of elastic structures in shallow water channels is of great significance for predicting and effectively controlling the structural vibration radiated noise of underwater vehicles, and is also one of the difficult problems in my country's underwater sound radiation research. Accurate prediction of radiated noise is the key to determining the safe activity radius of underwater vehicles to ensure their own concealment, which is of great research significance for ships, especially military ships.

[0003] The existing theoretical system has perfect solutions to the problem of radiated acoustic field of power sources in shallow sea channels, such as ray method, simple normal wave method, finite element method, etc. However, most of the existing technologies use point sound source equivalent source to simulate underwater structural sound source, which has low calculation accuracy and ignores the vibration distribution characteristics of the structure surface and the directional differences of sound radiation. In addition, in the calculation method of far-field and near-field acoustic field data in the modeling process, there is no good distinction between the distance of far-field and near-field, and thus when calculating the acoustic field data of the detection point, there must be irrationality in the selection of the algorithm.

[0004] Based on the technical defects existing in the above-mentioned prior art, how to propose a method that can improve the calculation accuracy of the model and accurately predict the radiated acoustic field of the shallow-water elastic structure at the detection point is an urgent problem that technicians in this field need to solve. Summary of the invention

[0005] In view of this, the present invention provides a method, system and storage medium for predicting three-dimensional structural sound field in a shallow sea channel.

[0006] In order to achieve the above object, the present invention provides the following technical solutions:

[0007] A method for predicting a three-dimensional structural sound field in a shallow sea channel comprises the following steps:

[0008] Step 1: Set n point sound sources and m surface sound sources inside the three-dimensional structure sound source as equivalent sources of the three-dimensional structure sound source, where n <m;

[0009] Step 2: Based on the surface velocity of the three-dimensional structural sound source and the Green's function of the equivalent source, the equivalent source method is used to obtain the intensity of the equivalent source inside the three-dimensional structural sound source;

[0010] Step 3: Based on the intensity of each equivalent source, the sound radiation model is established using the multi-physics field coupling FEM theory;

[0011] Step 4: Based on the sound radiation model established in step 3, analyze the sound radiation directivity to obtain the far-field distance of the sound radiation of the three-dimensional structure sound source. The area outside the far-field distance of the three-dimensional structure sound source is the far-field area, and the area within the far-field distance of the three-dimensional structure sound source is the near-field area.

[0012] Step 5: For the near field area, use the sound radiation model established in step 3 to obtain the near field sound radiation characteristics. For the far field area, use the parabolic equation method to calculate the far field sound radiation characteristics in steps.

[0013] Optionally, in step 1, the number of the point sound sources is about 1 / 10 of the surface sound sources, the point sound sources are evenly distributed inside the three-dimensional structure, and the point sound sources are not coplanar with the surface sound sources.

[0014] Optionally, in step 2, the radiated sound field of the equivalent source is obtained according to the shallow sea boundary condition as the Green's function of the equivalent source.

[0015] Optionally, in step four, based on the sound radiation directivity field points of the sound radiation model at different water depths and radiation radii, the boundary element method is used to obtain the sound radiation directivity of the three-dimensional structure sound source, and the sound radiation directivity diagram is drawn to obtain the far-field distance of the sound radiation of the three-dimensional structure sound source.

[0016] The present invention also provides a three-dimensional structural sound field prediction system in a shallow sea channel, comprising:

[0017] The equivalent source determination module is used to set n point sound sources and m surface sound sources inside the three-dimensional structure sound source as the equivalent sources of the three-dimensional structure sound source, where n <m;

[0018] An equivalent source intensity determination module is used to obtain the intensity of the equivalent source inside the three-dimensional structural sound source using the equivalent source method based on the surface velocity of the three-dimensional structural sound source and the Green's function of the equivalent source;

[0019] Acoustic radiation model building module, used to build the acoustic radiation model using multi-physics field coupling FEM theory;

[0020] The far-field distance determination module is used to analyze the sound radiation directivity based on the established sound radiation model to obtain the far-field distance of the sound radiation of the three-dimensional structure sound source. The area outside the far-field distance of the three-dimensional structure sound source is the far-field area, and the area within the far-field distance of the three-dimensional structure sound source is the near-field area.

[0021] The sound radiation information calculation module uses the established sound radiation model to obtain the near-field sound radiation characteristics for the near-field area, and uses the parabolic equation method to step-by-step calculate the far-field sound radiation characteristics for the far-field area.

[0022] A computer storage medium having a computer program stored thereon, wherein when the computer program is executed by a processor, the steps of a method for predicting a three-dimensional structural sound field in a shallow sea channel as described in any one of the above are implemented.

[0023] It can be seen from the above technical solutions that the present invention discloses a method, system and storage medium for predicting three-dimensional structural sound field in shallow water channels, which have the following beneficial effects compared with the prior art:

[0024] (1) The present invention combines the equivalent point sound source and the equivalent surface sound source as the equivalent source of the three-dimensional structural sound source in the shallow sea channel, which can more accurately simulate the underwater three-dimensional structure model, thereby improving the calculation accuracy of the model and ensuring the uniqueness of the solution at the characteristic frequency.

[0025] (2) The present invention first sets up multiple underwater elastic structure equivalent sources, and then uses the equivalent source method to obtain the strength of each equivalent source, providing a basis for the three-dimensional structure in the subsequent sound radiation model.

[0026] (3) During the modeling process, it is necessary to establish a coupling model of multiple models such as an underwater environment model and a three-dimensional elastic structure model. Therefore, the construction of a three-dimensional elastic structure model is extremely important. The present invention combines a surface sound source with a point sound source and obtains the intensity of each equivalent source, thereby constructing a more accurate underwater structure sound radiation model, which can more accurately simulate the sound radiation of an underwater elastic structure.

[0027] (4) Furthermore, since the finite element method (FEM) involves grid division, its computing power and sound field calculation distance are limited. Therefore, the sound radiation model established by the FEM method has higher computing efficiency and accuracy for near-field sound field calculations. However, for the far field, other methods are required for calculation. Based on this, the present invention uses the parabolic equation method to step-by-step calculate the far-field sound radiation characteristics, so that the calculations of the far-field sound field and the near-field sound field have higher accuracy and efficiency.

[0028] (5) Furthermore, the present invention also takes into account the issue of far-field distance. The distinction between far field and near field is extremely important for the sound field calculation of the detection point. Corresponding methods should be used to calculate the sound field at different detection points. Therefore, the present invention analyzes the directivity of sound radiation to obtain the far-field distance of the sound radiation of the three-dimensional structural sound source, and then accurately obtains the far-field area and near-field area of ​​the sound radiation, and then uses the corresponding method to calculate the sound field, thereby further ensuring the accuracy of the sound field calculation. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only the embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained according to the provided drawings.

[0030] Figure 1 It is the flowchart of the method steps of the present invention;

[0031] Figure 2 It is the schematic diagram of the system structure of the present invention. Detailed implementation manners

[0032] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0033] The embodiments of the present invention disclose a three-dimensional structure sound field prediction method under a shallow sea channel. Refer to Figure 1 , including the following steps:

[0034] Step 1: Set n point sources and m surface sources inside the three-dimensional structure sound source as the equivalent sources of the three-dimensional structure sound source, where n < m; the number of point sources is about 1 / 10 of the surface sources, the point sources are evenly distributed inside the three-dimensional structure, and the point sources and the surface sources are not coplanar.

[0035] Step 2: Based on the surface vibration velocity of the three-dimensional structure sound source and the Green's function of the equivalent source, use the equivalent source method to obtain the intensity of the equivalent source inside the three-dimensional structure sound source.

[0036] Specifically, establish a coordinate system according to the shallow sea environment, and obtain the radiation sound field of the equivalent source as the Green's function of the equivalent source according to the shallow sea boundary conditions, where the Green's function is k zn is the wave number in the depth direction, is the second-kind zero-order Hankel function, k rn is the wave number in the direction of the axis parallel to the sea surface in the coordinate system, n is the normal mode number, N is the total number of normal mode patterns intercepted, j represents the sequence, and D is the water depth. Based on the Green's function of the equivalent source, numerically fit the relationship function between the equivalent source intensity and the surface vibration velocity of the three-dimensional structure sound source. According to the relationship function and the surface vibration velocity of the three-dimensional structure sound source, the intensity of each equivalent source can be obtained.

[0037] Step 3: Based on the intensity of each equivalent source, the multi-physics field coupling FEM theory is used to establish the acoustic radiation model. Specifically, the FEM model of acoustic radiation of three-dimensional structures under shallow sea is established through fluid-solid coupling, organic boundary coupling and PML technology.

[0038] Step 4: Based on the sound radiation model established in step 3, analyze the sound radiation directivity to obtain the far-field distance of the sound radiation of the three-dimensional structure sound source. The area outside the far-field distance of the three-dimensional structure sound source is the far-field area, otherwise it is the near-field area. Specifically, input excitation to the model, and use the boundary element method to obtain the sound radiation directivity of the three-dimensional structure sound source according to the sound radiation directivity field points of the sound radiation model at different water depths and radiation radii, draw the sound radiation directivity diagram, and obtain the far-field distance of the sound radiation of the three-dimensional structure sound source.

[0039] Step 5: For the near field area, use the sound radiation model established in step 3 to obtain the near field sound radiation characteristics, and for the far field area, use the parabolic equation method to step-by-step calculate the far field sound radiation characteristics. Specifically, the sound field information at the junction of the far field area and the near field area is obtained based on the sound radiation model, which is used as the coupling condition for the near field area sound radiation FEM model and the far field PE (parabolic equation) model. The piecewise cubic Hermite interpolation method is used to match the FEM sound field information results with the PE initial field space grid, and then the implicit finite difference method is used to solve the PE to calculate the sound field information of the test point in the far field area.

[0040] The present invention also provides a three-dimensional structure sound field prediction system in a shallow sea channel, see Figure 2 ,include:

[0041] The equivalent source determination module is used to set n point sound sources and m surface sound sources inside the three-dimensional structure sound source as the equivalent sources of the three-dimensional structure sound source, where n <m;

[0042] An equivalent source intensity determination module is used to obtain the intensity of the equivalent source inside the three-dimensional structural sound source using the equivalent source method based on the surface velocity of the three-dimensional structural sound source and the Green's function of the equivalent source;

[0043] Acoustic radiation model building module, used to build the acoustic radiation model using multi-physics field coupling FEM theory;

[0044] The far-field distance determination module analyzes the directivity of sound radiation based on the established sound radiation model to obtain the far-field distance of the sound radiation of the three-dimensional structure sound source. The area outside the far-field distance of the three-dimensional structure sound source is the far-field area, and the area within the far-field distance of the three-dimensional structure sound source is the near-field area.

[0045] The sound radiation information calculation module uses the established sound radiation model to obtain the near-field sound radiation characteristics for the near-field area, and uses the parabolic equation method to step-by-step calculate the far-field sound radiation characteristics for the far-field area.

[0046] A computer storage medium having a computer program stored thereon, wherein when the computer program is executed by a processor, the steps of a method for predicting a three-dimensional structural sound field in a shallow sea channel as described in any one of the above are implemented.

[0047] In this specification, each embodiment is described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the embodiments can be referred to each other. For the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the method part.

[0048] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for predicting three-dimensional structural sound field in a shallow sea channel, characterized in that: The following steps are involved: Step 1: Set n point sound sources and m surface sound sources inside the three-dimensional structure sound source as equivalent sources of the three-dimensional structure sound source, where n <m; Step 2: Based on the surface velocity of the three-dimensional structural sound source and the Green's function of the equivalent source, the equivalent source method is used to obtain the intensity of the equivalent source inside the three-dimensional structural sound source; Step 3: Use multi-physics field coupling FEM theory to establish the sound radiation model; Step 4: Based on the sound radiation model established in step 3, analyze the sound radiation directivity to obtain the far-field distance of the sound radiation of the three-dimensional structure sound source. The area outside the far-field distance of the three-dimensional structure sound source is the far-field area, and the area within the far-field distance of the three-dimensional structure sound source is the near-field area. Step 5: For the near field area, use the sound radiation model established in step 3 to obtain the near field sound radiation characteristics. For the far field area, use the parabolic equation method to calculate the far field sound radiation characteristics in steps.

2. A method for predicting three-dimensional structural sound field in a shallow sea channel according to claim 1, characterized in that: In the step 1, the point sound sources are evenly distributed inside the three-dimensional structure, and the point sound sources are not coplanar with the surface sound sources.

3. The method for predicting three-dimensional structural sound field in a shallow sea channel according to claim 1, characterized in that: In the step 2, according to the shallow sea boundary condition, the radiated sound field of the equivalent source is obtained as the Green's function of the equivalent source.

4. The method for predicting three-dimensional structural sound field in a shallow sea channel according to claim 1, characterized in that: In the step 4, according to the sound radiation directivity field points of the sound radiation model at different water depths and radiation radii, the boundary element method is used to obtain the sound radiation directivity of the three-dimensional structure sound source, and the sound radiation directivity diagram is drawn to obtain the far-field distance of the sound radiation of the three-dimensional structure sound source.

5. A three-dimensional structural sound field prediction system in a shallow sea channel, characterized in that: include: The equivalent source determination module is used to set n point sound sources and m surface sound sources inside the three-dimensional structure sound source as the equivalent sources of the three-dimensional structure sound source, where n <m; An equivalent source intensity determination module is used to obtain the intensity of the equivalent source inside the three-dimensional structural sound source using the equivalent source method based on the surface velocity of the three-dimensional structural sound source and the Green's function of the equivalent source; Acoustic radiation model building module, used to build the acoustic radiation model using multi-physics field coupling FEM theory; The far-field distance determination module is used to analyze the sound radiation directivity based on the established sound radiation model to obtain the far-field distance of the sound radiation of the three-dimensional structure sound source. The area outside the far-field distance of the three-dimensional structure sound source is the far-field area, and the area within the far-field distance of the three-dimensional structure sound source is the near-field area. The sound radiation information calculation module uses the established sound radiation model to obtain the near-field sound radiation characteristics for the near-field area, and uses the parabolic equation method to step-by-step calculate the far-field sound radiation characteristics for the far-field area.

6. A computer storage medium, characterized in that: The computer storage medium stores a computer program, and when the computer program is executed by the processor, the steps of the method for predicting the three-dimensional structural sound field in a shallow sea channel as described in any one of claims 1 to 4 are implemented.

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