Temporal high-order rotated-staggered-grid finite difference method of anisotropic media elastic wave equations

When numerically simulating the elastic wave field in anisotropic media using the rotated staggered grid finite difference method, numerical dispersion phenomena usually occur. To solve this problem, a time-domain high-order difference coefficient calculation model based on the coupling of Taylor expansion and sampling approximation method is proposed, and an improved space-time domain high-order rotating staggered grid scheme is constructed. To verify the performance of the modified algorithm, the improved algorithm is compared with the general staggered grid and other rotated staggered grids, and the dispersion degree and stability of each algorithm are analyzed. Through the results of numerical experiments, it is found that the algorithm improved by the optimization strategy of the difference operator coefficients based on the Taylor expansion and the sampling approximation method can significantly suppress the dispersion of the elastic wave field in isotropic media, VTI/TTI anisotropic media, and the modified BP model.