流-固耦合波动模拟及Scholte波特性研究

Study on fluid-solid coupled wave numerical simulation and Scholte wave characteristics

基于流-固耦合波动勒让德谱元模拟方案,通过数值算例研究了流-固界面上方震源作用下Scholte波的形成机理和特性。数值结果表明,当流体中P波波速大于固体S波速时,沿流-固界面法线方向,Scholte波的幅值在流体中的衰减速率大于固体,反之则小于固体。在此基础上,初步讨论了流体震源到流-固界面的距离与Scholte波波长比值这一参数对Scholte波幅值的影响,Scholte波幅值随该比值增加呈指数衰减,对该比值大于1.5的情形,流体震源激发的Scholte波基本可以忽略不计。上述结果对深入分析海底地震动震相具有一定意义。

Based on the spectral element method for space discretization, a scheme for numerical simulation of fluid-solid coupling wave propagation in infinite domain has been obtained. The characteristics of Scholte wave generated by the source near the fluid-solid interface are studied. Results show that in case the P wave velocity of fluid is greater than solid S wave, along the normal direction, interface Scholte amplitude attenuation rate in the water is greater than that in the solid, conversely, the attenuation rate in the solid is greater than that in the water. Moreover, the relationship between the energy of excited Scholte wave and the distance of source to the fluid-solid interface has been discussed. In case the distance of source to the fluid-solid interface is greater than 1.5 of dominant wave length of wave in the fluid or in the solid medium, the energy of excited Scholte wave can be neglected.