Bulletin of the Seismological Society of America; December 2009; v. 99; no. 6;
p. 3340-3354; DOI: 10.1785/0120080346
© 2009 Seismological Society of America
An Explicit Method Based on the Implicit Runge–Kutta Algorithm for Solving Wave Equations
Dinghui Yang,
Nian Wang,
Shan Chen, and
Guojie Song
Department of Mathematical Sciences, Tsinghua University, Beijing 100084, China dhyang{at}math.tsinghua.edu.cn
A new explicit differentiator series method based on the implicit Runge–Kutta method, called the IRK-DSM in brief, is developed for solving wave equations. To develop the new algorithm, we first transform the wave equation, usually described as a partial differential equation (PDE), into a system of first-order ordinary differential equations (ODEs) with respect to time t. Then we use a truncated differentiator series method of the implicit Runge–Kutta method to solve the semidiscrete ordinary differential equations, while the high-order spatial derivatives included in the ODEs are approximated by the local interpolation method. We analyze the theoretical properties of the IRK-DSM, including the stability criteria for solving the 1D and 2D acoustic-wave equations, numerical dispersion, discretizing error, and computational efficiency when using the IRK-DSM to model acoustic-wave fields. For comparison, we also present the stability criteria and numerical dispersion of the so-called Lax–Wendroff correction (LWC) methods with the fourth-order and eighth-order accuracies for the 1D case. Promising numerical results show that the IRK-DSM provides a useful tool for large-scale practical problems because it can effectively suppress numerical dispersions and source-noises caused by discretizing the acoustic- and elastic-wave equations when too-coarse grids are used or the models have a large velocity contrast between adjacent layers. Theoretical analysis and numerical modeling also demonstrate that the IRK-DSM, through combining both the implicit Runge–Kutta scheme with good stability condition and the approximate differentiator series method, is a robust wave-field modeling method.
Copyright © 2010 by Seismological Society of America