CN-122015971-A - Underwater acoustic tomography inversion precision and measurement distance improving method and system based on flexible acoustic energy reinforced material

CN122015971ACN 122015971 ACN122015971 ACN 122015971ACN-122015971-A

Abstract

The application provides an underwater acoustic tomography inversion precision and measurement distance improving method and system based on flexible acoustic energy reinforced material, which carries out simulation experiment of parameter continuously changing along with position according to the Snell's law, determines sound velocity and thickness parameters of the flexible acoustic energy reinforced material to be prepared through the relation between refractive index and sound velocity, and calculating the mass fraction of the matrix and the scatterer of the flexible acoustic energy reinforced material, then segmenting the flexible acoustic energy reinforced material based on parameter values, respectively preparing the flexible acoustic energy reinforced material to obtain the flexible acoustic energy reinforced material, and finally inverting the temperature and the flow velocity through the transmission time difference of two host signals to realize real-time temperature flow monitoring. The application can meet the long-term real-time observation demands of most estuaries and coastal area water flows, has the advantages of continuous monitoring, high energy utilization rate, high space-time resolution, wide coverage, non-contact measurement, less required sites, strong adaptability and the like, and provides technical support for hydrologic monitoring engineering.

Inventors

YU XIAOJIAN
Bu Zhenxuan
ZHANG JINHU
LIN SHAOCHUAN
LIU CHENG
CHEN WENJIE
LIN LINGLI
XIE ZHAOYAN

Assignees

闽南师范大学

Dates

Publication Date: 20260512
Application Date: 20260225

Claims (6)

1. An underwater acoustic tomography inversion precision and measurement distance lifting method based on flexible acoustic energy enhancement materials is characterized by comprising the following steps: 1) According to the Snell's law, carrying out a simulation experiment of continuously changing parameters along with the position to obtain a refractive index, determining the sound velocity of the flexible sound energy reinforcing material to be prepared according to the relation between the refractive index and the sound velocity, and further adjusting the optimized parameters in the simulation experiment, and determining thickness parameters after observing the effect so as to ensure that the sound pressure amplification is consistent with the amplification of each frequency point and the wave beam width; 2) Segmenting the flexible acoustic energy reinforcing material according to the range of acoustic velocity parameters, and selecting one acoustic velocity of the middle area of each segment as the acoustic velocity of the flexible acoustic energy reinforcing material; 3) After the sound velocity of each section is designed, calculating the mass fraction of a matrix and a scattering body of the flexible sound energy reinforcing material, and then segmenting the flexible sound energy reinforcing material based on parameter values to prepare the flexible sound energy reinforcing material; 4) Uniformly weighing A, B components of high-elastomer organosilicon with equal mass of a matrix and tungsten powder or glycerin scatterer with corresponding mass fraction by using an electronic day, fully stirring until the components are uniformly mixed, putting the mixture into a vacuum box to remove air mixed in the mixture, pouring the degassed mixture into a mould, and heating the mould in a constant temperature box at 60-80 ℃ until the mixture is solidified and formed; 5) The mold is adjusted outwards as the thickness of the next acoustic layer without being taken out after the preparation of the acoustic layer is finished, the preparation of the next acoustic layer material is continued at the two ends, and the material is naturally bonded with the upper layer in the solidification process of the layer; 6) Repeating the preparation process of the step 5) to finish the preparation of other acoustic wave layer materials, thereby obtaining the flexible acoustic energy reinforced material; 7) The flexible acoustic energy enhancement material is used in an acoustic chromatography system, and the temperature and the flow velocity are inverted through the transmission time difference of two host signals, so that real-time temperature flow monitoring is realized.
2. The method for improving the accuracy and the measurement distance of the underwater acoustic tomography inversion based on the flexible acoustic energy enhancement material according to claim 1, wherein in the step 1), simulation experiments of continuous change of parameters along with the position are performed according to the snell's law, and the sound velocity and thickness parameters of the flexible acoustic energy enhancement material to be prepared are determined according to the relation between the refractive index and the sound velocity, and the specific steps are as follows: The simulation experiment is carried out in COMSOL software, a model comprising a transducer and a flexible sound energy reinforcing material is established, sound pressure of sound waves passing through the flexible sound energy reinforcing material is obtained in the experiment, a columnar transducer used in the system is CT60, the height is 42mm, the diameter is 28mm, the height, the width and the thickness of the flexible sound energy reinforcing material are initially set, the sound wave range and the specific use environment are fully covered by the height, the upper opening angle and the lower opening angle of the CT60 are 50 degrees, the range is covered as far as possible, the width corresponds to the cylindrical surface of the transducer, the refractive index of the flexible sound energy reinforcing material continuously changes along with the position, the change range of sound velocity is determined, the sound velocity regulation limit value of the flexible sound energy reinforcing material is comprehensively considered to determine the width, the sound field is regulated and observed in the experiment, and finally the thickness of the flexible sound energy reinforcing material is 1.5cm, the height is 7cm, and the total width is 12cm.
3. The method for improving the underwater acoustic tomography inversion precision and the measurement distance based on the flexible acoustic energy enhancement material according to claim 1 is characterized in that in the step 2), the sound velocity of the selected flexible acoustic energy enhancement material is the sound velocity of the center of the section, and the final sound velocity is obtained through simulation experiments, wherein in the simulation experiments, the sound pressure of each frequency point in the working frequency of 40kHz-80kHz is amplified by the flexible acoustic energy enhancement material at least to 5dB and is more consistent with the amplification as a standard determination parameter, after the material is used, the minimum peak value in the peak values of each frequency point is not less than about-4 dB of the maximum peak value and is more consistent with the change trend of angles, the sound pressure amplification on a focusing axis is more than 6dB, and the beam width of-3 dB after the sound signal passes through the flexible acoustic energy enhancement material is in the range of 10 DEG-15 deg.
4. The method for improving the accuracy and the measurement distance of the underwater acoustic tomography inversion based on the flexible acoustic energy enhancement material according to claim 1, wherein in the simulation experiment of the step 1), the refractive index is obtained according to the following formula: wherein n is refractive index, x is distance from the center point, F is distance from the transducer, and d is thickness.
5. The method for improving the accuracy and the measurement distance of the underwater acoustic tomography inversion based on the flexible acoustic energy enhancement material according to claim 1 is characterized in that in the step 3), a matrix is high-elastomer organic silicon, a scattering body is tungsten powder or glycerin, and the mass fraction of the matrix and the scattering body is obtained by the following formula: wherein subscripts 0 and 1 represent the matrix and the scatterer respectively, Represents the volume fraction of the scatterer, ρ represents the density, K represents the bulk modulus, and G represents the shear modulus.
6. The underwater acoustic chromatography inversion precision and measurement distance lifting system based on the flexible acoustic energy enhancement material is characterized by comprising two sets of main units, acoustic sensor assemblies and water level monitoring units which are oppositely arranged, wherein the two sets of monitoring devices are oppositely arranged on two sides of a water body to be detected; The main unit is provided with a core controller, an acoustic signal processing module and a data transmission module, wherein the core controller consists of an industrial computer and an embedded software system and is used for running an acoustic signal receiving and transmitting program and analyzing, processing, storing data such as flow and the like; the system comprises an acoustic signal processing module, a core controller, a data transmission module, a high-precision GPS module, a communication module and a communication module, wherein the acoustic signal processing module is provided with an integrated data acquisition card, an underwater sound power amplifier and an amplifying and filtering circuit, the amplifying and filtering circuit is connected with the core controller, the underwater sound power amplifier and the integrated data acquisition card are sequentially connected with the amplifying and filtering circuit, the data transmission module is provided with the high-precision GPS module and the communication module, the high-precision GPS module and the communication module are connected with the core controller, the GPS module is used for determining the geographic position and time synchronization of two main units and realizing inversion calculation of flow velocity and temperature, the communication module is used for providing a network and realizing the function of real-time transmission of flow data so as to realize real-time online monitoring, and network conditions can be provided for a remote control host by personnel; The acoustic sensor assembly is provided with an acoustic sensor and an acoustic energy enhancer, the acoustic sensor is provided with an underwater acoustic transducer and a hydrophone, the underwater acoustic transducer and the hydrophone are oppositely arranged on two sides of a water body to be detected, the underwater acoustic transducer is used for converting a voltage signal into an acoustic signal and transmitting the acoustic signal, and the hydrophone is used for receiving the acoustic signal in water and converting the acoustic signal into the voltage signal; The water level monitoring unit is connected with the main unit and used for measuring the water level in real time, and the arrangement depth of the water level monitoring unit is consistent with that of the acoustic sensor.

Description

Underwater acoustic tomography inversion precision and measurement distance improving method and system based on flexible acoustic energy reinforced material Technical Field The application belongs to the technical field of underwater acoustic water temperature and flow velocity monitoring, and particularly relates to an underwater acoustic tomography inversion precision and measurement distance improving method and system based on flexible acoustic energy reinforced materials. Background Underwater acoustic water temperature and flow rate monitoring is a non-invasive, high-precision water environmental parameter measurement technology, and is mainly based on the physical characteristic that the propagation speed of sound waves in water is influenced by temperature, salinity and pressure (depth). Because the estuary area has the characteristics of runoff and tide interaction, vertical water flow velocity layering and the like, the acoustic energy attenuation of the traditional technology is large, and real-time and long-distance monitoring is difficult to realize. If the temperature and salt depth meter is used for measuring insufficient space coverage in a large-area water area, the measurement range of the fixed-point acoustic Doppler flow profiler is limited, and the like. The acoustic chromatography technology is an emerging direction of estuary hydrologic monitoring by virtue of the advantages of high resolution and real-time measurement. The acoustic tomography utilizes an omnidirectional transducer to transmit and receive sound waves underwater, and utilizes propagation time and difference of acoustic receiving signals and transmitting signals to invert parameters such as temperature, flow and the like of a water area to be detected. However, in practical application, the technology is still limited by a plurality of key factors, namely high-frequency sound waves are greatly attenuated in water, the effective detection range is obviously limited, the accuracy of acoustic chromatography flow measurement can be reduced in high-noise environments such as extreme weather, and the like, and most of sound energy is invalid and dissipated due to the omnidirectional radiation characteristic of the transducer, so that the system has low energy efficiency, large interference and the like. Disclosure of Invention The application is made in view of the above problems, and an object of the application is to provide a method for improving the inversion accuracy and the measurement distance of underwater acoustic tomography based on a flexible acoustic energy enhancement material, which can effectively improve the utilization rate of acoustic energy without affecting the signal accuracy of an acoustic tomography system, solve the defects of low acoustic emission energy and large noise interference in the prior art, and effectively improve the inversion accuracy and the monitoring range of the system. The first aspect of the application provides an underwater acoustic tomography inversion precision and measurement distance improving method based on flexible acoustic energy enhancement materials, which comprises the following steps: 1) According to the simulation experiment, parameters are adjusted, thickness parameters are determined after the effect is observed, so that the sound pressure is amplified, and the frequency points are amplified and the beam width is consistent; 2) Segmenting the flexible acoustic energy reinforcing material according to the range of acoustic velocity parameters, and selecting one acoustic velocity of the middle area of each segment as the acoustic velocity of the flexible acoustic energy reinforcing material; 3) After the sound velocity of each section is designed, calculating the mass fraction of a matrix and a scattering body of the flexible sound energy reinforcing material, and then segmenting the flexible sound energy reinforcing material based on parameter values to prepare the flexible sound energy reinforcing material; 4) The method comprises the steps of (1) weighing A, B components of high-elastomer organosilicon (Ecoflex 00-30) with equal mass and corresponding mass fraction of scatterer (tungsten powder or glycerol) by using an electronic day, fully stirring until the components are uniformly mixed, putting the mixture into a vacuum box to remove air mixed in the mixture, pouring the degassed mixture into a mould, and heating the mixture in an incubator at about 70 ℃ until the mixture is solidified and molded; 5) After the preparation of the acoustic wave layer is finished, the mold is adjusted, the preparation of the next acoustic wave layer material is continued at the two ends, and the next acoustic wave layer material is naturally bonded with the previous layer in the solidification process; 6) And 5) repeating the preparation process of the step 5) to finish the preparation of other acoustic wave layer materials, thereby obtaining the flexible acoustic energy reinforce