Rapid correction method for target strength of scaling model for laying acoustic covering layer

Abstract

The invention discloses a rapid correction method for the target strength of a scaling model for laying an acoustic covering layer. The method belongs to the technical field of underwater target sound scattering, and comprises the following operation steps of: respectively determining the detection frequencies of a scaling model and a prototype according to an acoustic similarity condition; and establishing a three-dimensional model, constructing a corresponding light shell and laying acoustic covering layer model, and obtaining the target intensity of the light shell and laying acoustic covering layer of the scaling model under the detection frequency in the test. And the reflection coefficients of the acoustic covering layer under different frequency bands are obtained by calculating the target intensity difference before and after the acoustic covering layer is laid. And obtaining the target strength of the prototype laying acoustic covering layer through an acoustic similarity law and a target strength formula of the laying acoustic covering layer. According to the method, the target strength of the prototype laying acoustic covering layer can be rapidly obtained through the target strength of the laying acoustic covering layer scaling model, and important support is provided for the accuracy and reliability of an underwater laying acoustic covering layer scaling model test.

Description

Technical Field

[0001] The invention belongs to the technical field of underwater target sound scattering and relates to a method for quickly correcting the intensity of a scaled model target on which an acoustic covering layer is laid. Background Art

[0002] As an important part of maritime military forces, the stealth performance of ships has always attracted much attention. With the improvement of modern underwater vehicle noise reduction measures, especially the emergence of various acoustic covering layers with excellent performance, the stealth performance of underwater vehicles has been greatly improved.

[0003] Directly measuring the target strength of the original scale model after laying the acoustic covering layer requires a lot of manpower and material resources. Therefore, in actual engineering applications, the target strength of the scaled model laying the acoustic covering layer is often measured first, and then the target strength of the prototype laying the acoustic covering layer is obtained by using a correction method. The present invention proposes a correction method for the target strength of the scaled model laying the acoustic covering layer, which can correct the target strength of the scaled model laying the acoustic covering layer obtained by testing to obtain the target strength of the prototype laying the acoustic covering layer, so as to meet the actual engineering application. Summary of the invention

[0004] In view of the above problems, the purpose of the present invention is to propose a method for correcting the target strength of a scaled model of laying an acoustic covering layer. By this method, the target strength of the scaled model of laying an acoustic covering layer can be corrected to obtain the target strength of the prototype acoustic covering layer.

[0005] The technical solution of the present invention is: a method for quickly correcting the target strength of a scaled model for laying an acoustic covering layer according to the present invention, and the operating steps are as follows:

[0006] Step (1): using acoustic similarity conditions, determining the scale ratio between the scaled model and the prototype, and determining the detection frequency of the scaled model and the prototype;

[0007] Step (2): according to the determined detection frequencies of the scaled model and the prototype, the target intensity values ​​of the scaled model before and after the acoustic covering layer is laid under all frequency conditions are detected;

[0008] Step (3): according to the target intensity values ​​before and after the acoustic covering layer is laid, the reflection coefficient of the acoustic covering layer under different frequency band conditions is obtained;

[0009] Step (4): using the acoustic similarity relationship in step (1) and combining the transmit-receive combined target strength algorithm formula of the target for laying the acoustic covering layer, a correction method for the target strength of the scaled model for laying the acoustic covering layer is obtained;

[0010] Step (5): according to the reflection coefficient of the acoustic covering layer in different frequency bands obtained in step (3), the target strength of the scaled model after the acoustic covering layer is laid is calculated using the correction method in step (4) to obtain the prototype target strength after the acoustic covering layer is laid;

[0011] Step (6): Calculate the prototype target strength after laying the acoustic cover layer through simulation software and compare it with the target strength obtained in step (5) to verify the effectiveness and accuracy of the correction method.

[0012] Furthermore, in step (1), the acoustic similarity condition, in the case of a single frequency, requires that the acoustic quantities of corresponding points at corresponding frequencies are proportional to each other. The basic condition for satisfying the similarity can be obtained from the Helmholtz equation satisfied by simple harmonic sound waves under ideal fluid, static, and small amplitude conditions.

[0013] Further, specifically, the acoustic similarity condition is derived based on the Helmholtz equation, which is:

[0014]

[0015] In the formula, the quantity with ' represents the scaled model, and p is the scattered sound pressure. The prototype and the scaled model satisfy the Helmholtz equation in their respective systems. If the two systems are similar, the corresponding geometric scale, wave number and scattered sound pressure are proportional, and the similarity criterion of the unchanged Helmholtz number in the fluid medium can be obtained, that is, the corresponding dimensionless frequencies are equal; that is:

[0016] ka=const (2)

[0017] By definition, the prototype target intensity is based on a reference distance of 1m, namely:

[0018]

[0019] When all acoustic similarity conditions are met, a scaled model with a scale ratio of N is set. If the target intensity of the model is taken as the reference distance of 1m, according to the spherical attenuation law of the sound pressure in the far field The target strength TS′ of the scaled model is obtained, namely:

[0020] TS ′ =TS-20lgN (4)

[0021] It means that the target strength of the scaled model with a reference distance of 1m is reduced by 20lgN.

[0022] Further, specifically, the acoustic similarity condition, in the case of a single frequency, requires that the acoustic quantities of corresponding points at corresponding frequencies are proportional to each other. The basic condition for satisfying the similarity can be obtained from the Helmholtz equation satisfied by simple harmonic sound waves under ideal fluid, static, and small amplitude conditions; namely:

[0023]

[0024] Wherein, the quantity with ' represents the scaled model, and p is the scattered sound pressure.

[0025] Furthermore, if two systems are similar, the corresponding quantities are proportional, and there is a corresponding geometric scale ratio C a , the ratio of wave number scale C k The ratio of the scattered sound pressure to the p ; Substituting the corresponding ratio into formula (1), we get:

[0026]

[0027] For two systems to be similar, they must have:

[0028]

[0029] It means that the ratio of wave numbers should be equal to the inverse of the ratio of scales. This condition is the similarity criterion of the invariance of the Helmholtz number in the fluid medium, that is, the dimensionless frequencies are equal.

[0030] Further, in step (3), the reflection coefficient is:

[0031]

[0032] Where TS1 is the target strength of the model before laying the acoustic cover, and TS2 is the target strength of the model after laying the acoustic cover.

[0033] Furthermore, in step (4), the transmit-receive combined target strength algorithm formula of the acoustic cover layer target is based on the Kirchhoff formula, and the scattered sound field is:

[0034]

[0035] Satisfy rigid boundary conditions on the model surface:

[0036]

[0037] In the formula, φ i is the incident wave potential function, Then the scattering wave potential function in the case of combined transmission and reception is obtained as:

[0038]

[0039] Where, s is the surface of the scatterer, r1 and r2 are the incident and scattering point radius vectors respectively. In the case of combined transmission and reception, r1 = r2 = r; α1 and α2 are the angles between the normal direction of the outer surface and the incident wave and scattering point radius vectors. In the case of combined transmission and reception, α1 = α2 = α;

[0040]

[0041] In the formula, p0=p3, x2(n), y2(n) and z2(n) are the coordinates of the new coordinate system obtained by transforming the coordinates of points 1, 2 and 3 of the triangular mesh. They are represented in the program as follows:

[0042]

[0043] Where R is the distance between the transmitting transducer and the center of the plate.

[0044] Furthermore, the scattered sound pressure can be obtained from the above formula (13):

[0045] p s =REBIMA×REIM / (-4π) (14)

[0046] The target strength of the model without acoustic cover is:

[0047]

[0048] The scattered sound pressure of the model after applying the acoustic blanket:

[0049] p s1 =REIM×REAIMA / (-4π)×R (16)

[0050] Where R is the reflection coefficient matrix after interpolation;

[0051] At this time, the target strength of the model after laying the acoustic cover is:

[0052]

[0053] In the formula, R L is the distance between the receiving hydrophone and the model.

[0054] Furthermore, in step (4), the correction method includes acoustic similarity and a fast algorithm for target strength of acoustic covering layer laid by transmitting and receiving;

[0055] The correction method is through the formula Implement the correction of target intensity;

[0056] In the formula, To lay the prototype target strength of the acoustic blanket, TS f The target strength of the scaled model for laying the acoustic cover, R 1 is the reflection coefficient of the acoustic covering layer in the prototype test frequency band, R is the reflection coefficient of the acoustic covering layer in the scaled model test frequency band, and N is the scale ratio corresponding to the scaled model.

[0057] Further, specifically, the method for correcting the target strength of the scaled model for laying the acoustic covering layer is:

[0058]

[0059] In the formula, To lay the prototype target strength of the acoustic blanket, TS 1 is the prototype target strength, R 1 is the reflection coefficient of the acoustic cover layer in the prototype test frequency band, TS f is the target strength of the scaled model for laying the acoustic covering layer, TS is the target strength of the scaled model, and R is the reflection coefficient of the acoustic covering layer in the scaled model test frequency band; according to the acoustic similarity, that is:

[0060]

[0061] Where N is the scale ratio corresponding to the scaled model; the correction method for the target strength of the scaled model for laying the acoustic cover layer can be obtained:

[0062]

[0063] In the formula, To lay the prototype target strength of the acoustic blanket, TS f The target strength of the scaled model for laying the acoustic cover, R 1 is the reflection coefficient of the acoustic covering layer in the prototype test frequency band, R is the reflection coefficient of the acoustic covering layer in the scaled model test frequency band, and N is the scale ratio corresponding to the scaled model.

[0064] The beneficial effects of the present invention are as follows: the method for correcting the target strength of a scaled model for laying an acoustic covering layer of the present invention is based on the acoustic similarity theory and a method for quickly predicting the combined target strength of the transmitting and receiving units of the target for laying an acoustic covering layer, thereby realizing the correction of the target strength of the scaled model for laying an acoustic covering layer; the method proposed in the present invention can utilize relatively easy-to-obtain test data to correct the target strength of the scaled model for laying an acoustic covering layer to obtain the target strength of the prototype for laying an acoustic covering layer; a large amount of manpower and material resources are required for testing the target strength of an underwater vehicle model after laying an acoustic covering layer, and the method of the present invention can realize the rapid correction of the target strength of the scaled model for laying an acoustic covering layer in engineering applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0065] Figure 1 is a flow chart of target strength correction of acoustic cover layer laid by a scaled model in an embodiment of the present invention;

[0066] Figure 2 is a model diagram of an acoustic covering layer laid on a pressure hull in an embodiment of the present invention;

[0067] Figure 3 is a schematic diagram of a spherical shell model and a grid without an acoustic cover layer in an embodiment of the present invention;

[0068] Figure 4 It is a schematic diagram of a spherical shell model and a grid for laying an acoustic covering layer in an embodiment of the present invention;

[0069] Figure 5 is a comparison diagram of target strength before and after the spherical shell is provided with an acoustic covering layer in an embodiment of the present invention;

[0070] Figure 6 is a schematic diagram of the reflection coefficient of the acoustic covering layer in an embodiment of the present invention;

[0071] Figure 7 It is a frequency response curve diagram of target intensity correction of the acoustic covering layer laid on the spherical shell in an embodiment of the present invention. DETAILED DESCRIPTION

[0072] The specific technical scheme of the present invention is further described in detail below with reference to specific examples.

[0073] As shown in the figure, a method for correcting the target strength of a scaled model of an acoustic covering layer laid according to the present invention comprises the following steps:

[0074] S1: Using the acoustic similarity condition, according to the required target strength of the prototype of the acoustic covering layer, combined with the scale ratio corresponding to the scaled model, the detection frequency of the scaled model of the acoustic covering layer is determined through the acoustic similarity condition;

[0075] S2: testing the target strength of the scaled model before and after the acoustic covering is laid at two frequency bands according to the detection frequencies of the scaled model and the prototype determined in step S1;

[0076] S3: Based on the target intensity values ​​before and after the acoustic covering layer is laid, the reflection coefficient of the acoustic covering layer under different frequency band conditions is obtained, which is:

[0077]

[0078] Among them, TS1 is the target strength of the model before laying the acoustic cover layer, and TS2 is the target strength of the model after laying the acoustic cover layer;

[0079] S4: Using the acoustic similarity relationship in step S1, combined with the transmit-receive combined target strength algorithm formula of the target of laying the acoustic covering layer, a correction method for the scaled model target strength of laying the acoustic covering layer is obtained, which is:

[0080]

[0081] in, To lay the prototype target strength of the acoustic blanket, TS f The target strength of the scaled model for laying the acoustic cover, R 1 is the reflection coefficient of the acoustic covering layer in the prototype test frequency band, R is the reflection coefficient of the acoustic covering layer in the scaled model test frequency band, and N is the scale ratio corresponding to the scaled model;

[0082] S5: according to step S3, the reflection coefficients of the acoustic covering layer in different frequency bands are obtained, and then these reflection coefficients are applied to the scaled model to calculate the target strength of the scaled model after the acoustic covering layer is laid; using the correction method in step S4, the strength of the prototype target after the acoustic covering layer is finally determined;

[0083] S6: Calculate the prototype target strength after laying the acoustic cover layer through simulation software, and compare it with the target strength obtained in step S5 to verify the effectiveness and accuracy of the correction method.

[0084] Furthermore, the acoustic similarity condition in step S1, in the case of a single frequency, requires that the acoustic quantities of corresponding points at corresponding frequencies are proportional to each other. The basic condition for satisfying the similarity can be obtained from the Helmholtz equation satisfied by simple harmonic sound waves under ideal fluid, static, and small amplitude conditions; namely:

[0085]

[0086] Among them, the quantity with ' represents the scaled model, and p is the scattered sound pressure;

[0087] If two systems are similar, the corresponding quantities are proportional and have a corresponding geometric scale ratio C a , the ratio of wave number scale C k The ratio of the scattered sound pressure to the p ;

[0088] Substituting the corresponding ratio into formula (3), we get:

[0089]

[0090] For two systems to be similar, they must have:

[0091]

[0092] It means that the ratio of wave numbers should be equal to the inverse of the ratio of scales. This condition is the similarity criterion of the invariance of the Helmholtz number in the fluid medium, that is, the dimensionless frequencies are equal;

[0093] By definition, the prototype target intensity is based on a reference distance of 1m, namely:

[0094]

[0095] When all acoustic similarity conditions are met, a scaled model with a scale ratio of N is set. If the target intensity of the model is taken as the reference distance of 1m, according to the spherical attenuation law of the sound pressure in the far field Get the scaled model target strength TS′

[0096] TS ′ =TS-20lgN (7)

[0097] It means that the target strength of the scaled model with a reference distance of 1m is reduced by 20lgN.

[0098] Furthermore, the combined target strength algorithm formula of the acoustic cover layer used in step S4 is based on the Kirchhoff formula, and the scattered sound field is:

[0099]

[0100] Satisfy rigid boundary conditions on the model surface:

[0101]

[0102] Among them, φ i is the incident wave potential function (ignore e -iωt ), Then the scattering wave potential function in the case of combined transmission and reception is obtained as:

[0103]

[0104] In the above formula, s is the surface of the scatterer, r1 and r2 are the incident point and scattering point radius vectors respectively. In the case of combined transmission and reception, r1 = r2 = r; α1 and α2 are the angles between the normal direction of the outer surface and the incident wave and scattering point radius vectors. In the case of combined transmission and reception, α1 = α2 = α; that is:

[0105]

[0106] in, p0=p3, x2(n), y2(n) and z2(n) are the coordinates of the new coordinate system obtained by transforming the coordinates of points 1, 2 and 3 of the triangular mesh; that is:

[0107]

[0108] Where R is the distance between the transmitting transducer and the center of the plate;

[0109] The scattered sound pressure can be obtained from the above formula, that is:

[0110] REBIMB=REBIMA×REIM / (-4π) (13)

[0111] At this time, the target strength of the untiled model is,

[0112]

[0113] After applying the acoustic cover, the scattered sound pressure of the model is:

[0114] REBIMB1=REIM×REAIMA / (-4π)×R (15)

[0115] Where R is the reflection coefficient matrix after interpolation;

[0116] At this time, the target strength of the model after laying the anechoic tiles is:

[0117]

[0118] In the formula, R L is the distance between the receiving hydrophone and the model.

[0119] Furthermore, the method for correcting the target strength of the scaled model for laying the acoustic cover layer used in step S4 is:

[0120]

[0121] In the formula, To lay the prototype target strength of the acoustic blanket, TS 1 is the prototype target strength, R 1 is the reflection coefficient of the acoustic cover layer in the prototype test frequency band, TS f is the target strength of the scaled model of the acoustic covering layer, TS is the target strength of the scaled model, and R is the reflection coefficient of the acoustic covering layer in the scaled model test frequency band;

[0122] According to acoustic similarity,

[0123] TS 1 = TS+20logN (18)

[0124] Where N is the scale ratio corresponding to the scaled model;

[0125] The correction method of the target strength of the scaled model for laying the acoustic cover can be obtained, namely:

[0126]

[0127] Example

[0128] A method for correcting the target strength of a scaled model for laying an acoustic covering layer of the present invention comprises the following steps:

[0129] S1: Scale the spherical shell with a radius of 2m by the scale ratios of 2 and 3 respectively;

[0130] According to the acoustic similarity condition, the dimensionless frequency ka of the test frequency of the acoustic covering layer model is determined to be 12.56 to 37.69;

[0131] Combine the acoustic covering layer with the acoustic parameter model of the corresponding scaled model shell, and select the corresponding shell type for laying the acoustic covering layer. Because the acoustic covering layer no longer has the same acoustic properties as the prototype after being scaled, the acoustic covering layer used in the actual scaled model test is consistent with the acoustic covering layer used in the prototype.

[0132] The thickness of the acoustic covering layer is H1 = 50 mm, the thickness of the steel layer is H2 = 8 mm, and the specific material parameters are: rubber [density ρ1 = 1090 kg / m3; Young's modulus E1 = 3×10 7 Pa; Poisson's ratio μ = 0.49; loss factor δ = 0.249]; steel [density ρ2 = 7800 kg / m3; Young's modulus E2 = 2.1 × 10 11 Pa];

[0133] S2: Based on the scaled model and acoustic cover layer determined in step S1, the scaled models before and after the acoustic cover layer is laid are established using the finite element software COMSOL and the corresponding target strength is calculated; Figure 3 , Figure 4 As shown;

[0134] S3: According to the target strength of the scaled model before and after the acoustic covering layer is laid, the reflection coefficient of the acoustic covering layer is obtained, which is:

[0135]

[0136] Among them, TS1 is the target strength of the model before laying the acoustic cover layer, and TS2 is the target strength of the model after laying the acoustic cover layer;

[0137] S4: Using the acoustic similarity relationship in step S1, combined with the transmit-receive combined target strength algorithm formula of the target of laying the acoustic covering layer, a correction method for the scaled model target strength of laying the acoustic covering layer is obtained, which is:

[0138]

[0139] in, To lay the prototype target strength of the acoustic blanket, TS f The target strength of the scaled model for laying the acoustic cover, R 1 is the reflection coefficient of the acoustic covering layer in the prototype test frequency band, R is the reflection coefficient of the acoustic covering layer in the scaled model test frequency band, and N is the scale ratio corresponding to the scaled model;

[0140] S5: according to step S3, the reflection coefficients of the acoustic covering layer in different frequency bands are obtained, and then the reflection coefficients are applied to the scaled model to calculate the target intensity of the scaled model after the acoustic covering layer is laid;

[0141] Using the correction method in step S4, the strength of the prototype target after laying the acoustic covering layer is finally determined;

[0142] S6: Calculate the prototype target strength after laying the acoustic cover layer through simulation software, and compare it with the target strength obtained in step S5 to verify the effectiveness and accuracy of the correction method.

Claims

1. A method for quickly correcting the target strength of a scaled model for laying an acoustic covering layer, characterized in that: The operation steps are as follows: Step (1): using acoustic similarity conditions, determining the scale ratio between the scaled model and the prototype, and determining the detection frequency of the scaled model and the prototype; Step (2): according to the determined detection frequencies of the scaled model and the prototype, the target intensity values ​​of the scaled model before and after the acoustic covering layer is laid under all frequency conditions are detected; Step (3): according to the target intensity values ​​before and after the acoustic covering layer is laid, the reflection coefficient of the acoustic covering layer under different frequency band conditions is obtained; Step (4): using the acoustic similarity relationship in step (1) and combining the transmit-receive combined target strength algorithm formula of the target for laying the acoustic covering layer, a correction method for the target strength of the scaled model for laying the acoustic covering layer is obtained; Step (5): according to the reflection coefficient of the acoustic covering layer in different frequency bands obtained in step (3), the target strength of the scaled model after the acoustic covering layer is laid is calculated using the correction method in step (4) to obtain the prototype target strength after the acoustic covering layer is laid; Step (6): Calculate the prototype target strength after laying the acoustic cover layer through simulation software and compare it with the target strength obtained in step (5) to verify the effectiveness and accuracy of the correction method.

2. A method for quickly correcting the target strength of a scaled model for laying an acoustic covering layer according to claim 1, characterized in that: In step (1), the acoustic similarity condition is in the case of single frequency. The similarity requires that the acoustic quantities of corresponding points at corresponding frequencies are proportional to each other. The basic conditions for satisfying the similarity can be obtained from the Helmholtz equation satisfied by simple harmonic sound waves under ideal fluid, static, and small amplitude conditions.

3. A method for quickly correcting the target strength of a scaled model for laying an acoustic covering layer according to claim 2, characterized in that: Specifically, the acoustic similarity condition is derived based on the Helmholtz equation, which is: In the formula, the quantity with ' represents the scaled model, and p is the scattered sound pressure. The prototype and the scaled model satisfy the Helmholtz equation in their respective systems. If the two systems are similar, the corresponding geometric scale, wave number and scattered sound pressure are proportional, and the similarity criterion of the unchanged Helmholtz number in the fluid medium can be obtained, that is, the corresponding dimensionless frequencies are equal; that is: ka=const (2) By definition, the prototype target intensity is based on a reference distance of 1m, namely: When all acoustic similarity conditions are met, a scaled model with a scale ratio of N is set. If the target intensity of the model is taken as the reference distance of 1m, according to the spherical attenuation law of the sound pressure in the far field The target strength TS′ of the scaled model is obtained, namely: TS ′ =TS-20lgN (4) It means that the target strength of the scaled model with a reference distance of 1m is reduced by 20lgN.

4. A method for quickly correcting the target strength of a scaled model for laying an acoustic covering layer according to claim 3, characterized in that: Specifically, the acoustic similarity condition, in the case of a single frequency, requires that the acoustic quantities of corresponding points at corresponding frequencies are proportional to each other. The basic condition for satisfying the similarity can be obtained from the Helmholtz equation satisfied by simple harmonic sound waves under ideal fluid, static, and small amplitude conditions; Right now: Wherein, the quantity with ' represents the scaled model, and p is the scattered sound pressure.

5. A method for quickly correcting the target strength of a scaled model for laying an acoustic covering layer according to claim 3, characterized in that: If two systems are similar, the corresponding quantities are proportional and have a corresponding geometric scale ratio C a , the ratio of wave number scale C k The ratio of the scattered sound pressure to the p ; Substituting the corresponding ratio into formula (1), we get: For two systems to be similar, they must have: It means that the ratio of wave numbers should be equal to the inverse of the ratio of scales. This condition is the similarity criterion of the invariance of the Helmholtz number in the fluid medium, that is, the dimensionless frequencies are equal.

6. A method for quickly correcting the target strength of a scaled model for laying an acoustic covering layer according to claim 1, characterized in that: In step (3), the reflection coefficient is: Where TS1 is the target strength of the model before laying the acoustic cover, and TS2 is the target strength of the model after laying the acoustic cover.

7. A method for quickly correcting the target strength of a scaled model for laying an acoustic covering layer according to claim 1, characterized in that: In step (4), the transmit-receive combined target strength algorithm formula of the acoustic cover layer target is based on the Kirchhoff formula, and the scattered sound field is: Rigid boundary conditions are met on the model surface: In the formula, φ i is the incident wave potential function, Then the scattering wave potential function in the case of combined transmission and reception is obtained as: Where, s is the surface of the scatterer, r1 and r2 are the incident and scattering point radius vectors respectively. In the case of combined transmission and reception, r1 = r2 = r; α1 and α2 are the angles between the normal direction of the outer surface and the incident wave and scattering point radius vectors. In the case of combined transmission and reception, α1 = α2 = α; In the formula, p0=p3, x2(n), y2(n) and z2(n) are the coordinates of the new coordinate system obtained by transforming the coordinates of points 1, 2 and 3 of the triangular mesh. They are represented in the program as follows: Where R is the distance between the transmitting transducer and the center of the plate.

8. A method for quickly correcting the target strength of a scaled model for laying an acoustic covering layer according to claim 7, characterized in that: From the above formula (13), the scattered sound pressure can be obtained: p s =REBIMA×REIM / (-4π) (14) The target strength of the model without acoustic cover is: The scattered sound pressure of the model after applying the acoustic blanket: p s1 =REIM×REAIMA / (-4π)×R (16) Where R is the reflection coefficient matrix after interpolation; At this time, the target strength of the model after laying the acoustic cover is: In the formula, R L is the distance between the receiving hydrophone and the model.

9. A method for quickly correcting the target strength of a scaled model for laying an acoustic covering layer according to claim 1, characterized in that: In step (4), the correction method includes acoustic similarity and a fast algorithm for target strength of acoustic covering layer laid by transmitting and receiving; The correction method is through the formula Implement the correction of target intensity; In the formula, To lay the prototype target strength of the acoustic blanket, TS f The target strength of the scaled model for laying the acoustic cover, R 1 is the reflection coefficient of the acoustic covering layer in the prototype test frequency band, R is the reflection coefficient of the acoustic covering layer in the scaled model test frequency band, and N is the scale ratio corresponding to the scaled model.

10. A method for quickly correcting the target strength of a scaled model for laying an acoustic covering layer according to claim 9, characterized in that: Specifically, the method for correcting the target strength of the scaled model for laying the acoustic covering layer is: In the formula, To lay the prototype target strength of the acoustic blanket, TS 1 is the prototype target strength, R 1 is the reflection coefficient of the acoustic cover layer in the prototype test frequency band, TS f is the target strength of the scaled model for laying the acoustic covering layer, TS is the target strength of the scaled model, and R is the reflection coefficient of the acoustic covering layer in the scaled model test frequency band; according to the acoustic similarity, that is: TS 1 = TS+20logN (19) Where N is the scale ratio corresponding to the scaled model; the correction method for the target strength of the scaled model for laying the acoustic cover layer can be obtained: In the formula, To lay the prototype target strength of the acoustic blanket, TS f The target strength of the scaled model for laying the acoustic cover, R 1 is the reflection coefficient of the acoustic covering layer in the prototype test frequency band, R is the reflection coefficient of the acoustic covering layer in the scaled model test frequency band, and N is the scale ratio corresponding to the scaled model.

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