多孔介质水平分层海底低频地震波的数值模拟  

A Numerical Simulation of Seismic Wave Caused by Low Frequency Sound Source in Shallow Sea with Thick Porous Sediment by Staggered-grid Finite Difference Method

作　　者：卢再华[1] 张志宏[1] 顾建农[1] 

机构地区：[1]海军工程大学理学院,湖北武汉430033

出　　处：《兵工学报》2014年第12期2065-2071,共7页Acta Armamentarii

基　　金：国家自然科学基金项目(51179195);国防基金项目(513030203-02)

摘　　要：舰船低频辐射噪声在海底岩土层中引起的弹性波被称为舰船地震波,可用于识别舰船目标。为获取浅海厚沉积层环境下舰船地震波的传播特性,基于多孔介质波动理论建立海底地震波的三维交错网格有限差分算法,对多孔介质海底低频声源激励的海底地震波进行数值计算。计算结果表明:近场范围内,多孔介质海底地震波的波动成分主要有透射快纵波、透射横波、透射慢纵波和海底界面波;对于远场地震波而言,海水层的波导效应逐渐表现出来,海底地震波的波动成分主要是沿水平方向传播的简正波和海底界面波。Elastic wave in the seabed caused by low frequency noise radiated from ship is the so-called ship seismic wave which can be used to identify ship target.In order to obtain the propagation characteristics of ship seismic wave in shallow sea with thick porous sediment,a 3D staggered grid finite difference algorithm for calculating seismic wave at seafloor is presented based on Biot wave theory for porous elastic sediment.Numerical calculation of seismic wave caused by low frequency sound source in a typical shallow sea environment is carried out.The calculated results show that the components of seismic wave in the near field include not only fast P-wave,slow P-wave and S-wave transmitted into the sediment,but also an interface wave which propagates nearby the seafloor.However in the far field,the wave components of seismic wave are mainly normal modes and interface wave,the former propagates mainly in the waveguide of sea water and the latter propagates along the seafloor.

关 键 词：振动与波 多孔介质 低频 浅海 地震波 交错网格 

分 类 号：P733.23[天文地球—物理海洋学]