Numerical Accuracy Analysis of Triangle-based Discontinuous Galerkin Method for Elastic Waves

Summary The Discontinuous Galerkin Method (DGM) which is a high-order finite element method capable of adapting to the complex surface conditions has attracted extensive attention. In this paper we investigate the numerical dispersion and dissipation of DGM on triangular mesh for elastic wave equations. A periodic triangular mesh is applied in which the basic element can be any isosceles triangle. Thus, we can analyse the numerical accuracy with regard to grid types more effectively. The local Lax-Friedrichs flux and the 3rd – order TVD Runge-Kutta time scheme are adopted in analysis which are also widely used in application. We conclude that in DGM numerical dispersion and dissipation show similar numerical anisotropy which is related to the type of grids. Then, further experiments reveal that using unstructured mesh achieves a better modelling result than using structured mesh in DGM.