Elastic finite-difference method for irregular grids
Elastic finite-difference method for irregular grids
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DOI：
10.1190/1.1444520
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发表时间：
1999-02
期刊：
影响因子：
3.3
通讯作者：
I. Oprsal;J. Zahradník
中科院分区：
文献类型：
--
作者：
I. Oprsal;J. Zahradník
复杂结构的有限差分 (FD) 建模需要简单的算法。本文提出了一种新的空间不规则网格弹性有限元方法，该方法简单，同时节省了大量的内存和计算时间。断层、低速层、空腔和/或非平面表面等特征在精细网格上进行处理，而模型的其余部分则以相同的精度在粗网格上表示。由于矩形网格单元，精细部分和粗糙部分之间不需要插值。在本方法中，小网格步长和大网格步长之间的相对突然的转变不会产生数值伪影。平面或非平面自由表面（包括地下空腔）的处理方式与内部网格点类似，但考虑了自由表面外部的零值弹性参数和密度（真空形式主义）。给出了真空形式满足自由表面条件的理论证明。数值验证是...
Finite‐difference (FD) modeling of complicated structures requires simple algorithms. This paper presents a new elastic FD method for spatially irregular grids that is simple and, at the same time, saves considerable memory and computing time. Features like faults, low‐velocity layers, cavities, and/or nonplanar surfaces are treated on a fine grid, while the remaining parts of the model are, with equal accuracy, represented on a coarse grid. No interpolation is needed between the fine and coarse parts due to the rectangular grid cells. Relatively abrupt transitions between the small and large grid steps produce no numerical artifacts in the present method. Planar or nonplanar free surfaces, including underground cavities, are treated in a way similar to internal grid points but with consideration of the zero‐valued elastic parameters and density outside the free surface (vacuum formalism). A theoretical proof that vacuum formalism fullfills the free‐surface conditions is given. Numerical validation is per...