Researches on very low frequency acoustic signal propagation characteristics in different shallow elastic wedge bottoms

Jun Tang,J. Yin,Hanhao Zhu,Jun Zhu,Guangxue Zheng,V. Goussev

doi:10.1051/matecconf/201928302003

Jun Tang, J. Yin + Show 4 more

Open Access

https://doi.org/10.1051/matecconf/201928302003

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Abstract

Targeted at the issue of extremely low-frequency (<100Hz) acoustic propagation in complex shallow elastic bottom environments. The influence law of different complex elastic bottoms on the acoustic signal propagation at very low frequency by acoustic energy flux has been analyzed with the simulation, which is based on the finite element method. The elastic bottoms which have been studied are the shallow horizontal elastic bottom, and the up-sloping and the down-sloping elastic bottom. The results show that the acoustic signal propagating in the up-sloping and down-sloping elastic bottom environments is more complex than that propagating in the horizontal elastic bottom, and the acoustic energy leaking into those elastic bottoms has very different influence on the acoustic signal propagation, especially in the up-sloping bottom.

Highlights

The shallow water environment has attracted more attention in the current study of the underwater acoustics application
To study the acoustic signal propagation characteristics in the sloping shallow water environment, we have conducted the simulated analysis on the influence laws of different complex elastic bottoms on the low-frequency acoustic signal propagation with the help of acoustic energy flux[1,2] and a commercial finite-element code FEM[3,4] developed by COMSOL AB
The acoustic energy flux propagating in different complex elastic boom environments has been simulated on the FE method

Summary

Introduction

The shallow water environment has attracted more attention in the current study of the underwater acoustics application. In the study of traditional shallow water environment simulation, the Pekeris waveguide has been used to analyse the acoustic propagation. The influence of the acoustic signal propagating in the shallow sloping elastic bottom environment is more complex than that of the acoustic signal propagating in the horizontal shallow water environment. The research on the acoustic signal propagation characteristics in the sloping shallow water environment has been emphasized. To study the acoustic signal propagation characteristics in the sloping shallow water environment, we have conducted the simulated analysis on the influence laws of different complex elastic bottoms on the low-frequency acoustic signal propagation with the help of acoustic energy flux[1,2] and a commercial finite-element code FEM[3,4] developed by COMSOL AB. Because FEM solves the sound field problem by dividing the environment into discrete units, it can solve the complex sound propagation problem more accurate than the traditional method which is solved by equations and boundary conditions

Calculation of acoustic energy flux in the waveguide

Study on acoustic propagation characteristics of elastic bottom environments

Conclusions