波动方程正演模拟边界条件的比较分析

Comparison and analysis of boundary conditions for seismic wave equation forward modeling

通过数值模拟研究了透明边界、Clayton-Engquist边界和完全匹配层边界的吸收效果,得出如下结论:在反射角和频率相同的情况下,完全匹配层边界条件效果最好,ClaytonEngquist边界效果次之,而透明边界条件的效果最差。以边界条件对100 Hz模型边界垂直反射的吸收效果来衡量,完全匹配层边界条件与Clayton-Engquist边界条件的效果分别是透明边界条件的16.5倍和3.5倍。在<40 Hz的低频范围内,或者在反射角>65°的情况下,Clayton-Engquist边界相对透明边界的吸收效果相对优势显著变弱。而完全匹配层边界的吸收效果则在150Hz频率范围内和75°反射角范围内始终保持稳定的相对优势。

This paper compares and studies the transparent boundary condition（TBC）,ClaytonEngquist（CE）absorbing boundary condition and perfectly matched layer（PML）absorbing boundary condition by the numerical simulation and gets the following conclusions.Under the same frequency and reflection angle to the model edges,the absorbing effect of PML is the best among the three types of boundary conditions,that of CE is the second and that of TBC is the worst.For the vertical reflections of 100 Hz from the model edges,the absorbing effect of PML and CE are 16.5and 3.5times,respectively,of TBC.The advantage of CE over TBC significantly reduces when the frequency is40Hz or the angle of reflection is65°.However,PML stably keeps its advantage over CE and TBC when the frequency is over a range of 150 Hz and the model edge reflection angle is over a range of 75°.