交错网格在伪谱法弹性波场数值模拟中的应用

摘要

In order to eliminate the interfere pseudo-wave caused by numerical computation in the elastic wavefield modeling by pseudo-spectral method, we analyzed the reasons leading to the phenomena, and introduced staggered grids into elastic wavefield modeling by pseudo-spectral method. The numerical oscillation in wavefield modeling is overcome by joint computation of central grids and staggered grids (first-order spatial derivative is calculated by staggered grids and second-order spatial derivative is calculated by central grids). Model testing result indicates that the method can effectively remove the interfere pseudo-wave and make the modeling result stable, accurate and reliable.%为消除伪谱法弹性地震波场数值模拟中因数值计算产生的干扰伪波,分析了伪谱法弹性波场数值计算产生干扰伪波的原因,提出在伪谱法弹性波场数值模拟时引入交错网格,采用中心网格和交错网格联合计算的方式(即:采用交错网格计算一阶导数,采用中心网格计算二阶导数)来克服波场计算过程中的数值振荡现象.模型计算结果表明,该方法可以有效消除伪谱法模拟波场中的干扰伪波,使波场计算值稳定、准确、可靠.