曲线坐标系下的完全匹配层吸收边界条件  

A Perfectly Matched Layer Absorbing Boundary Condition Under the Curvilinear Coordinate System

作　　者：刘志强[1] 孙建国[1] 孙辉[1] 刘明忱 高正辉[1] 石秀林[1] Liu Zhiqiang;Sun Jianguo;Sun Hui;Liu Mingchen;Gao Zhenghui;Shi Xiulin(GeoExploration of Science and Technology, Jilin University, Changchun 130026, China)

机构地区：[1]吉林大学地球探测科学与技术学院,长春130026

出　　处：《吉林大学学报（地球科学版）》2017年第6期1875-1884,共10页Journal of Jilin University：Earth Science Edition

基　　金：国家自然科学基金项目(41274120;41404085;41504084)~~

摘　　要：在地震波数值模拟中,需要采用吸收边界条件以吸收人为边界反射。本文针对曲线坐标系下的二阶弹性波方程提出了一种完全匹配层(PML)吸收边界条件。与直角坐标系下的PML吸收边界条件类似,曲线坐标系下的PML吸收边界条件是一种在频率域中给出的人工边界条件,由相应的复坐标变换得到。在变换到时间域后,完全匹配层中将出现复杂的卷积运算。为了避免这些卷积运算,引入了4个中间变量。为了简化自由边界条件,采用正交贴体网格对起伏地表模型进行网格剖分。数值算例表明,该方法可以有效消除人为边界反射。An absorbing boundary condition is needed to absorb the artificial boundary reflections in a numerical simulation of seismic wave.We presented a perfectly matched layer(PML)absorbing boundary condition for a secondorder elastic wave equation in a curvilinear coordinate system.Similar to the PML in a Cartesian coordinate system,the PML absorbing boundary condition in a curvilinear coordinate system was formulated in frequency domain,which was obtained by the corresponding complex coordinate transformation.To transform the condition into time domain will result in complex convolutions in the perfectly matched layer.To avoid these convolutions,we introduced4intermediate variables.Furthermore,to simplify the free boundary condition,we adopted the orthogonal bodyfitted grid for mesh generation of a rugged topography model.The numerical results show that the proposed method can absorb artificial boundary reflections effectively.

关 键 词：人为边界反射 完全匹配层吸收边界 正交贴体网格 

分 类 号：P631.4[天文地球—地质矿产勘探]