A weight-adjusted discontinuous Galerkin method for wave propagation in coupled elastic-acoustic media

This paper presents a high-order discontinuous Galerkin (DG) scheme for the simulation of wave propagation through coupled elastic-acoustic media. We use a first-order stress -velocity formulation, and derive a simple upwind-like numerical flux which weakly imposes continuity of the normal velocity and traction at elastic-acoustic interfaces. When combined with easily invertible weight-adjusted mass matrices [1-3], the resulting method is efficient, consistent, and energy stable on curvilinear meshes and for arbitrary heterogeneous media, including anisotropy and sub-cell (micro) heterogeneities. We numerically verify the high order accuracy and stability of the proposed method, and investigate its performance for applications in photoacoustic tomography. (C) 2020 Elsevier Inc. All rights reserved.