Method for positioning vibration noise source of ship in ship pool

Abstract

The invention provides a method for positioning a ship vibration noise source in a ship pool, and the method comprises the steps: constructing a double-layer envelope surface sound pressure measurement array in the ship pool, and building a ship radiation and pool wall reflection sound field model; establishing a sound field analysis model for inward and outward radiation of a semi-free space cylindrical surface, and constructing a semi-space double-cylindrical surface sound pressure-sound pressure transfer matrix; according to the amplitude and phase of sound pressure measured by double envelope surfaces, ship radiation and reflection sound in a ship pool is separated, and ship vibration noise source positioning in an open half-space water area is realized based on the ship radiation sound in the ship pool and based on a three-dimensional noise source positioning method formed by half-space virtual source wave beams. According to the half-space virtual source beam forming method, the actual acoustic propagation condition and the boundary effect of the ocean can be fully considered, and the spatial distribution and radiation characteristics of a ship noise source in a free sea area are directly obtained through mathematical mapping of a ship pool measurement field and an open water area target field.

Description

Technical Field

[0001] This invention relates to the field of underwater acoustic engineering, specifically to a method for locating vibration noise sources of ships within a ship pool. Background Technology

[0002] The underwater radiated acoustic level of a warship is a core indicator for evaluating its acoustic stealth performance, directly impacting the success or failure of target detection, sonar tracking, and underwater warfare. Traditional acoustic field testing mainly relies on two methods: sea-based measurements and tank trials. Sea-based measurements can comprehensively acquire the ship's mechanical noise, hydrodynamic noise, and propeller noise, but their deployment cycle is long, and sea conditions and environmental noise interference (ocean turbulence, biological noise, shipping noise, etc.) are complex and variable. This not only results in high testing costs but also makes it difficult to support the high-frequency, short-cycle assessment requirements for acoustic field performance during the ship design phase.

[0003] In contrast, shipboard test tanks (including semi-anechoic tanks and dedicated test tanks) offer a controllable, low-cost, and short-cycle testing environment. They also provide natural isolation from external noise, enabling rapid measurement of radiated sound from mechanical vibrations in the early design stages, significantly improving sound field testing efficiency. However, the tank interior exhibits significant wall reflections, creating a complex reverberant sound field where the ship's own radiated sound and the reflected sound from the tank walls superimpose and interfere with each other. Under these acoustic conditions, traditional sound level measurement methods struggle to effectively distinguish between direct radiated sound and multiple reflections, making it impossible to accurately locate and extract features from local vibration sources on the ship—such as the main engine gear system, pump and valve systems, and pipeline excitation points.

[0004] Therefore, there is an urgent need to develop a novel method for locating ship vibration and noise sources. This method should retain the advantages of short-cycle, low-cost, and controllable environment of pool testing, while possessing good robustness and wide-bandwidth applicability for in-pool sound field separation and half-space noise source localization. This would meet the needs of early assessment and optimization of acoustic stealth performance during the ship design phase, thereby improving the iterative efficiency of ship acoustic stealth design and providing a solid technical foundation for future acoustic early warning, noise prediction, and intelligent noise management. Summary of the Invention

[0005] The purpose of this invention is to solve the above-mentioned problems and provide a method for locating ship vibration noise sources in the ship pool. It uses a fixed hydrophone and two semi-circular ring hydrophone linear arrays that move along the length of the ship. Through equally spaced translation operations and reference phase calibration, the sound pressure of the entire double-layer cylindrical envelope surface is collected. By trading time for space, this method effectively reduces the complexity and economic cost of the system, and is especially suitable for engineering maintenance and cost control.

[0006] To achieve the above objectives, the present invention adopts the following technical solution.

[0007] A method for locating ship vibration and noise sources within a ship pool includes constructing a double-layer envelope surface sound pressure measurement array within the ship pool and establishing a sound field model for ship radiation and pool wall reflection; establishing an analytical model of the inward and outward radiation sound field of a semi-free space cylindrical surface and constructing a semi-space double-cylindrical surface sound pressure-sound pressure transfer matrix; separating the ship's radiated and reflected sound within the ship pool based on the amplitude and phase of the sound pressure measured by the double envelope surface; and then, based on the ship's radiated sound within the ship pool and a three-dimensional noise source location method based on the formation of a semi-space virtual source beam, realizing the location of ship vibration and noise sources in an open semi-space water area.

[0008] Furthermore, the double-layer envelope acoustic pressure measurement array in the ship pool includes a fixed hydrophone and two semi-circular hydrophone arrays with their axes located on the water surface and symmetrical about the ship.

[0009] Furthermore, the spacing between each element of the semi-circular hydrophone array is less than one-third of the wavelength of the upper limit analysis frequency.

[0010] Furthermore, the semi-circular hydrophone array is moved horizontally along the axial direction.

[0011] Furthermore, the distance the double-layer envelope acoustic pressure measurement array moves within the ship pool is less than one-third of the wavelength of the upper limit analysis frequency each time.

[0012] Furthermore, the array element acquires signals and performs Fourier transform to obtain a complex sound pressure spectrum, including the inner envelope surface sound pressure and the outer envelope surface sound pressure.

[0013] Furthermore, according to the principle of sound field superposition, the sound pressure of the inner envelope surface and the sound pressure of the outer envelope surface are superimposed by the sound pressure radiated by the ship and the sound pressure reflected by the wall.

[0014] Furthermore, according to the Helmholtz integral principle, the ship radiated sound pressure received by the outer envelope surface is uniquely determined by the ship radiated sound pressure received by the inner envelope surface, and the wall-scattered sound pressure received by the inner envelope surface is uniquely determined by the wall-scattered sound pressure received by the outer envelope surface. Based on the sound pressure complex spectrum measured by the inner and outer envelope surfaces and the sound pressure-sound pressure transfer matrix of the double-layer envelope surface, the ship radiated sound pressure can be separated. Then, based on the three-dimensional noise source localization method formed by the half-space virtual source beam, the ship vibration noise source can be located in the open half-space water area.

[0015] Furthermore, by symmetrically introducing virtual sources at the sound source location, phase cancellation of the interface reflection field is achieved, and the sensor-received signals are coherently weighted and superimposed on the three-dimensional scanning grid, thereby accurately estimating the location of the noise source.

[0016] Furthermore, the complex pressure signal received by the multi-channel sensor is loaded and normalized to its maximum amplitude. Multiple scanning points are preset in space, and the distance from the sensor of each hydrophone to the true source field and the virtual source field is calculated.

[0017] This invention utilizes a three-dimensional noise source localization method based on half-space virtual source beamforming for naval noise source localization in open waters. The positive effect of this method in achieving actual open water naval noise source localization and prediction is as follows:

[0018] (1) This invention constructs a half-space acoustic model and introduces a virtual source beamforming algorithm, which can effectively suppress reverberation field interference and separate the actual radiated sound field of the ship based on the sound pressure data measured in the ship pool, thereby achieving high-precision localization of noise sources in three-dimensional space. Furthermore, by utilizing this localization result, the measurement data in the ship pool can be accurately mapped to the open water environment, providing a data basis for the prediction of the distribution of ship noise sources in actual sea areas.

[0019] (2) The half-space virtual source beamforming method proposed in this invention can fully consider the actual acoustic propagation conditions and boundary effects in the ocean. By mathematically mapping the measurement field in the ship pool to the target field in the open water, the spatial distribution and radiation characteristics of ship noise sources in free sea areas can be directly obtained. Compared with the traditional measurement method based on the overall sound level, this method is no longer limited by the influence of complex reflections and reverberation, and significantly improves the spatial resolution and applicable frequency bandwidth of sound source localization.

[0020] (3) This invention enables rapid and accurate localization and prediction of ship noise sources in actual open waters, greatly reducing reliance on expensive sea trials and complex numerical simulations, shortening the testing and evaluation cycle, and reducing testing costs. This method is applicable to various engineering scenarios such as ship acoustic stealth design, active sonar optimization, and noise source anomaly diagnosis. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the dual semi-circular ring sound pressure measurement array provided in an embodiment of the present invention.

[0022] Figure 2 This is a schematic diagram of the parallel-formed double-cylinder envelope surface provided in an embodiment of the present invention.

[0023] Figure 3 This is a schematic diagram of the double-envelope surface sound pressure-sound pressure transmission matrix provided in an embodiment of the present invention.

[0024] Figure 4 This is a color schematic diagram of the simulation results of the total sound pressure of the double cylindrical envelope surface in a ship pool environment provided by an embodiment of the present invention.

[0025] Figure 5 This is a color schematic diagram of the transfer matrix provided in an embodiment of the present invention.

[0026] Figure 6 This is the noise source localization result of the 25Hz sound source in the boat pool environment provided in the embodiment of the present invention.

[0027] Figure 7This is the noise source localization result of the 50Hz sound source in the boat pool environment provided in the embodiment of the present invention.

[0028] Figure 8 This is the noise source localization result of a 100Hz sound source in a boat pool environment provided in the embodiment of the present invention.

[0029] Figure 9 This is the noise source localization result of a 200Hz sound source in a boat pool environment provided in the embodiment of the present invention.

[0030] Figure 10 This is the noise source localization result of the 400Hz sound source in the boat pool environment provided in the embodiment of the present invention. Detailed Implementation

[0031] The following describes a specific embodiment of a method for locating ship vibration and noise sources within a ship pool according to the present invention, with reference to the accompanying drawings. However, it should be noted that the specific embodiments described are not intended to limit the specific implementation of the present invention. Any similar structures or variations employing the present invention should be included within the scope of protection of the present invention. The following description of the embodiments is based on the accompanying drawings and is used to illustrate specific embodiments in which the present invention can be implemented. Formulas and other references mentioned in the embodiments are used to illustrate and understand the present invention, and are not intended to limit the present invention.

[0032] See Figures 1-10 A method for locating ship vibration noise sources within a ship pool includes constructing a double-layer envelope surface sound pressure measurement array within the ship pool and establishing a sound field model for ship radiation and pool wall reflection; establishing an analytical model of the inward and outward radiation sound field of a semi-free space cylindrical surface and constructing a semi-space double-cylindrical surface sound pressure-sound pressure transfer matrix; separating the ship's radiated and reflected sound from the pool based on the amplitude and phase of the sound pressure measured on the double envelope surface. The double-layer envelope surface sound pressure measurement array within the ship pool includes a fixed hydrophone and two semi-circular ring hydrophone arrays with their axes located on the water surface and symmetrical about the ship. The spacing between each element of the semi-circular ring hydrophone array is less than one-third of the wavelength of the upper limit analysis frequency. The semi-circular ring hydrophone array moves horizontally along the axial direction, and the distance moved by the double-layer envelope surface sound pressure measurement array within the ship pool is less than one-third of the wavelength of the upper limit analysis frequency each time.

[0033] The array element acquires signals and performs Fourier transform to obtain a complex sound pressure spectrum, including the sound pressure of the inner and outer envelope surfaces. According to the principle of sound field superposition, the inner and outer envelope sound pressures are the superposition of the ship's radiated sound pressure and the wall-reflected sound pressure. According to the Helmholtz integral principle, the ship's radiated sound pressure received by the outer envelope surface is uniquely determined by the ship's radiated sound pressure received by the inner envelope surface, and the wall-reflected sound pressure received by the inner envelope surface is uniquely determined by the wall-reflected sound pressure received by the outer envelope surface. The ship's radiated sound pressure can be separated from the complex sound pressure spectra measured by the inner and outer envelope surfaces and the double-layer envelope surface sound pressure-sound pressure transfer matrix. Furthermore, based on a three-dimensional noise source localization method using half-space virtual source beamforming, the location of ship vibration noise sources in open half-space water areas can be achieved.

[0034] A method for locating ship vibration noise sources within a ship pool includes a fixed hydrophone and multiple semi-circular hydrophone arrays. The spacing between each element of the semi-circular hydrophone array is less than one-third of the wavelength of the upper limit analysis frequency. The semi-circular hydrophone array moves horizontally along an axial direction, with each movement distance being less than one-third of the wavelength of the upper limit analysis frequency. The method includes two semi-circular hydrophone arrays.

[0035] This technical solution is generally divided into four parts: 1. Constructing a double-layer envelope surface sound pressure measurement array in the ship pool and establishing a sound field model of ship radiation and pool wall reflection; 2. Establishing an analytical model of the inward and outward radiation sound field of a semi-free space cylindrical surface and constructing a semi-space double cylindrical surface sound pressure-sound pressure transfer matrix; 3. Separating ship radiation and reflection sound in the ship pool based on the amplitude and phase of the sound pressure measured by the double envelope surface; and 4. Using a spatial virtual source beamforming method to locate ship noise sources.

[0036] A semi-circular ring sound pressure measurement system in a ship pool, sound pressure measurement and correction on a double cylindrical envelope surface, separation of ship-radiated and reflected sound in the ship pool; a double cylindrical surface sound pressure-sound pressure transfer matrix, a sound field model for ship pool radiation and reflection; a spatial virtual source beamforming method, and ship noise source localization.

[0037] 1. Double semi-circular ring sound pressure measurement system in the ship's pool

[0038] A fixed hydrophone is suspended directly below the ship. Two semi-circular hydrophone arrays with their axes on the water surface and symmetrical about the ship are deployed. The spacing between each array element is less than one-third of the wavelength of the upper limit analysis frequency. The array is moved horizontally along the axis direction, while the sound pressure of the double-layer cylindrical envelope is measured. The distance between each movement must also be less than one-third of the wavelength of the upper limit analysis frequency. Figure 1 In the middle, there are two ring-shaped bands, which are semi-circular hydrophone arrays. The smaller black dot on the left is a fixed hydrophone, and the larger one on the left is a low-frequency transducer (xn,0,zn).

[0039] The signal acquired by each array element is subjected to Fourier transform to obtain the sound pressure complex spectrum, where the sound pressures of the inner and outer envelope surfaces are denoted as [insert values ​​here]. and Where f is the line spectrum frequency of interest, normalized for the output sound pressure of a fixed hydrophone measured at the same time basis, i.e. and

[0040] 2. Construct a model of the radiation and reflection sound field in the ship pool.

[0041] According to the principle of sound field superposition, the sound pressure measured by the two envelope surfaces is the sound pressure p radiated by the ship. i (f) and wall-reflected sound pressure p s (f) Superposition, i.e.

[0042]

[0043] According to the Helmholtz integral principle, the ship's radiated sound pressure received by the outer envelope surface is uniquely determined by the ship's radiated sound pressure received by the inner envelope surface.

[0044]

[0045] Where G(r,r) s ) is the Green's function for a free field in half-space.

[0046]

[0047] Similarly, the wall-scattered sound pressure received by the inner envelope surface is uniquely determined by the wall-scattered sound pressure received by the outer envelope surface.

[0048]

[0049] United

[0050] {P i 1}=([T2]·[T1]-I) -1 ·([T2]·{p 2}-{p 1}) (5)

[0051] Where [T1] and [T2] are the sound pressure-sound pressure transfer matrices from the inside to the outside and from the outside to the inside, respectively. It can be seen that the ship's radiated sound pressure can be separated from the sound pressure complex spectrum measured at the inner and outer envelope surfaces and the sound pressure-sound pressure transfer matrix of the double-layer envelope surface.

[0052] 3. Double cylindrical surface sound pressure-sound pressure transfer matrix

[0053] Rapid and robust calculation of the sound pressure-sound pressure transfer matrices [T1] and [T2] of the inner and outer envelope surfaces is key to separating the ship's radiated sound and the wall-reflected sound within the hull.

[0054] The physical meaning of the sound pressure-sound pressure transfer matrix [T1] on the inner to outer envelope surface is the sound pressure received by the outer cylinder when the sound pressure in the current region (which satisfies that it is much smaller than the wavelength of the sound wave) is 1 and the sound pressure in other regions is 0. In the case that it is much smaller than the wavelength of the sound wave, this region is related to the area and is not sensitive to the shape. To simplify the analysis, it is approximated as a rectangle with two sides parallel to the z-axis.

[0055] Establish a cylindrical coordinate system with the cylinder axis as the z-axis. The free liquid surface is located at θ = 0° and θ = 180°, and the coordinates of the inner and outer cylindrical surfaces are r = a and r = b, respectively. Without loss of generality, let the coordinates of the center of the radiation surface be (a, θ1, 0), the height be 2z0, the included angle be 2θ0, and the coordinates of the observation point be (b, θ2, z2-z1).

[0056] Figure 3 In the middle, the left side is [T1]; the right side is [T2].

[0057] In cylindrical coordinates, the general solution of the radiated sound field is:

[0058]

[0059] in

[0060]

[0061] Utilizing orthogonality, i.e.

[0062]

[0063] The expansion coefficients can be determined.

[0064]

[0065] Substituting into equation (6) yields the elements of the transfer matrix [T1].

[0066] The sound pressure-sound pressure transfer matrix [T2] of the outer envelope surface from the outside to the inside, physically represents the sound pressure received by the inner cylinder when the sound pressure in the front region is 1 and the sound pressure in other surface elements is 0, radiating inward from the outer cylinder in a semi-free space. The general solution of the sound field is as follows:

[0067]

[0068] The expansion coefficients can be determined based on orthogonality (8).

[0069]

[0070] Substituting these elements into equation (10) yields the elements of the transfer matrix [T2].

[0071] Substituting into equation (5), the radiated sound of the inner envelope surface can be determined.

[0072] 4. A three-dimensional sound source localization beamforming method based on the half-space virtual source method

[0073] By symmetrically introducing virtual sources at the sound source location, phase cancellation of the interface reflection field is achieved. The sensor-received signals are coherently weighted and superimposed on a three-dimensional scanning grid, thereby accurately estimating the location of the noise source.

[0074] Load the complex pressure signal received by the multi-channel sensor {p i}, and normalize it using its maximum amplitude:

[0075]

[0076] Multiple scanning points r = (x, y, z) are preset in space. For each sensor i (position r... i Calculate the distances to the true source field and the virtual source field respectively:

[0077] R i =||r i -r||,R′ i =||r i -r′||.

[0078] Construct the complex steering vector components:

[0079]

[0080] The first term represents true source radiation, and the second term represents virtual source radiation, used for reflection and cancellation.

[0081] For the scan point r, calculate the normalized beam output:

[0082]

[0083] To facilitate comparison, further normalization was performed:

[0084]

[0085] In all preset scan point sets {r j In}, find the Largest index

[0086]

[0087] and corresponding coordinates As a noise source, its location can be estimated. To evaluate positioning accuracy, it can be...

[0088] The Euclidean distance between the known true source location s and the known true source location s is used as an error index:

[0089]

[0090] Example 1: Using the method proposed in this patent, an evaluation and analysis of the ship vibration and noise source localization method in a ship pool environment is performed. A low-frequency transducer is placed at a spatial coordinate of (-0.05m, -0.01m, -0.71m) in a water pool, emitting single-frequency signals at frequencies of 25Hz, 50Hz, 100Hz, 200Hz, and 400Hz. Sound pressure is measured through a double cylindrical envelope surface. The total sound pressure test results of the double cylindrical envelope surface are input into the system. The 25Hz result is shown in [link to example]. Figure 4 .

[0091] Based on equations (6) and (10), construct the sound pressure-sound pressure transfer matrices [T1] and [T2] of the inner and outer envelope surfaces. Figure 5 In the figure, the top one is the inner envelope surface sound pressure-sound pressure transfer matrix [T1], and the bottom one is the outer envelope surface sound pressure-sound pressure transfer matrix [T2].

[0092] A three-dimensional sound source localization beamforming method based on the half-space virtual source method is proposed. It can be seen that this method can accurately locate the position of noise sources in the ship's pool at different frequencies.

[0093] Figures 6 to 10 The localization results of low-frequency noise sources at different frequencies are 25Hz, 50Hz, 100Hz, 200Hz, and 400Hz. The actual noise source locations are (-0.05m, -0.01m, -0.71m). It can be seen that the noise source location predicted by this method is basically consistent with the actual noise source location, which fully proves the feasibility of this patented method.

Claims

1. A method for locating vibration and noise sources of ships within a ship pool, characterized in that, This includes constructing a double-layer envelope surface sound pressure measurement array within the ship pool, establishing a sound field model for ship radiation and pool wall reflection; establishing an analytical model for the inward and outward radiation sound field of a semi-free space cylindrical surface, and constructing a semi-free space double cylindrical surface sound pressure-sound pressure transfer matrix; Based on the amplitude and phase of the sound pressure measured by the double envelope surface, the radiated and reflected sound of the ship in the pool is separated. Then, based on the radiated sound of the ship in the pool, a three-dimensional noise source localization method based on the virtual source beam formation in half space is used to locate the ship vibration noise source in an open half space water area.

2. The method for locating ship vibration and noise sources in a ship pool according to claim 1, characterized in that, The double-layer envelope acoustic pressure measurement array in the ship pool includes a fixed hydrophone and two semi-circular hydrophone arrays with their axes located on the water surface and symmetrical about the ship.

3. The method for locating ship vibration and noise sources in a ship pool according to claim 2, characterized in that, The spacing between each element of the semi-circular hydrophone array is less than one-third of the wavelength of the upper limit analysis frequency.

4. The method for locating ship vibration and noise sources in a ship pool according to claim 3, characterized in that, The semi-circular hydrophone array moves horizontally along the axial direction.

5. The method for locating ship vibration and noise sources in a ship pool according to claim 4, characterized in that, The double-layer envelope acoustic pressure measurement array inside the ship pool moves at distances less than one-third of the wavelength of the upper limit analysis frequency each time.

6. The method for locating ship vibration and noise sources in a ship pool according to claim 5, characterized in that, The array element acquires signals and performs Fourier transform to obtain a complex sound pressure spectrum, including the inner envelope surface sound pressure and the outer envelope surface sound pressure.

7. The method for locating ship vibration and noise sources in a ship pool according to claim 6, characterized in that, According to the principle of sound field superposition, the sound pressure of the inner envelope surface and the sound pressure of the outer envelope surface are superimposed by the sound pressure radiated by the ship and the sound pressure reflected by the wall.

8. The method for locating ship vibration and noise sources in a ship pool according to claim 7, characterized in that, According to the Helmholtz integral principle, the ship's radiated sound pressure received by the outer envelope surface is uniquely determined by the ship's radiated sound pressure received by the inner envelope surface, and the wall-scattered sound pressure received by the inner envelope surface is uniquely determined by the wall-scattered sound pressure received by the outer envelope surface. Based on the sound pressure complex spectrum measured by the inner and outer envelope surfaces and the sound pressure-sound pressure transfer matrix of the double-layer envelope surface, the ship's radiated sound pressure can be separated. Then, based on the three-dimensional noise source localization method formed by the half-space virtual source beam, the ship vibration noise source can be located in the open half-space water area.

9. A method for locating ship vibration and noise sources in a ship pool according to claim 8, characterized in that, By symmetrically introducing virtual sources at the sound source location, phase cancellation of the interface reflection field is achieved. The sensor-received signals are coherently weighted and superimposed on a three-dimensional scanning grid, thereby accurately estimating the location of the noise source.

10. A method for locating ship vibration and noise sources in a ship pool according to claim 9, characterized in that, The complex pressure signal received by the multi-channel sensor is loaded and normalized to its maximum amplitude. Multiple scanning points are preset in space, and the distances to the true source field and the virtual source field are calculated for each hydrophone sensor.

Images