LBM Study Of Sound Propagation In Inhomogeneous Sonic Fluid Medium

The ocean contains rich resources,which are not fully exploited by human beings.With the increase of population and the gradual shortage of land resources,people are paying more and more attention to the exploitation and utilization of marine resources.In the marine environment,the sound wave propagation attenuation is slowly,the propagation distance is long,the sound wave is the main way of the information transmission in the sea.Therefore,it is of great significance to study the law of sound wave propagation in the ocean.It is well known that sea water is an inhomogeneous medium,and the propagation law of sound wave in sea water is relatively complex,in which the sound velocity in sea water is an important factor affecting its propagation law.The change of sound speed in sea water is generally very small compared with itself,so that the sound propagation characteristics may be greatly changed,the results show that the sound energy distribution,the sound propagation distance and the sound propagation time have obvious changes.Therefore,the accurate value of sound velocity is very important in theoretical research and engineering.However,the methods of studying the propagation characteristics of sound wave in deep sea usually simulate the fluid medium with constant or stratified sound velocity,but the sound velocity does not change continuously in the whole space.Therefore,based on the lattice Boltzmann method,the numerical simulation of sound propagation in non-uniform sound-velocity fluid is studied in this paper.(1)an improved Buick model is proposed in this paper.By analyzing the lattice Boltzmann model,a suitable velocity adjustable model,the Buick model is selected,and then the model is improved to make the velocity of sound change in space.(2)the model is used to simulate the nonlinear effect of sound wave and the attenuation of one-dimensional plane wave.The simulation results are in good agreement with the theoretical solution.(3)a modified Buick model is used to simulate the sound propagation in deep-sea channel in the background of deep-sea environment.In the course of simulation,the parameters vary with space,so that the sound velocity also changes in space.Compared with the 2014 South China Sea experiment,the model can be used to simulate the sound propagation in the medium with inhomogeneous sound velocity.(4)By changing the depth of the sound source,the influence of the sound source frequency on the sound propagation in the deep-sea channel is studied.