SIMULATION OF PML ABSORBING BOUNDARY CONDITION WITH SECOND-ORDER ELASTIC WAVE EQUATION IN ANISOTROPIC MEDIA
各向异性介质中二阶弹性波方程模拟PML吸收边界条件

A new alternative perfectly matched layer (PML) absorbing boundary condition is developed to attenuate the artificial boundary reflections generated in numerical simulation of the second-order elastic wave equation. The second-order equation can be described by displacement, which is more appropriate than the first-order one. Its PML condition conventionally needs to split the displacement into four parts, which occupies a large amount of memory and requires solving a third-order differential equation in time. As for the other choice, non-splitting PML method may be applied to the second-order equation, but it requires solving the dual integral in time. The new method can solve or simplity the above problems. Finally, a staggered-grid finite difference method with this PML condition is used to simulate an anisotropic media model and the results show that the method is efficient.