一种有效的处理模型角点反射的方法

An Effective Method for Handling the Corner Reflections of a Model

1. 石油大学,北京102200;2. 胜利石油管理局勘探事业部,东营257001

Petroleum University, Beijing 102200

波动方程有限差分数值模拟过程中,由于人为边界的引入,必然会导致边界反射,从而影响数值模拟的效果。为此人们提出了各种吸收边界条件方程,但是大部分吸收边界条件都很少专门考虑如何处理好模型边界角点的反射问题。本文在研究前人工作的基础上,提出了一种有效的处理边界角点反射的方法—插值预测波场法,即利用波前面的概念估算出边界角点上入射波的方向,再根据边界角点附近模型内部的波场值,利用非线性插值预测出边界角点处的波场值。数值算例表明了这种方法的有效性。

Boundary reflections, which will damage the effects of simulation, are present inevitably because of the introduction of man made boundaries when the simulation was carried out via finite difference of wave equation. To solve this problem, various absorbing boundary conditions have been figured out, which, however, seldom consider how to deal with corner reflections of the model. To cope with the corner reflections, a new and effective method, called prediction of wave field by interpolation, is presented in this paper based on exiting researches. The method first determines the incident directions of reflections at the corner using wavefront, then estimates the wavefield values at the corner of the model by means of nonlinear interpolation. The validity of the method was demonstrated by numerical experiments.