GPU-accelerated discontinuous Galerkin methods on hybrid meshes

• We present an energy-stable low-storage high order discontinuous Galerkin method for the wave equation.
• We describe algorithms for efficient implementation on Graphics Processing Units (GPUs).
• We derive order-dependent global and local timestep restrictions for DG on hybrid meshes.
• We verify high order convergence and computational efficiency with numerical experiments.

We present a time-explicit discontinuous Galerkin (DG) solver for the time-domain acoustic wave equation on hybrid meshes containing vertex-mapped hexahedral, wedge, pyramidal and tetrahedral elements. Discretely energy-stable formulations are presented for both Gauss–Legendre and Gauss–Legendre–Lobatto (Spectral Element) nodal bases for the hexahedron. Stable timestep restrictions for hybrid meshes are derived by bounding the spectral radius of the DG operator using order-dependent constants in trace and Markov inequalities. Computational efficiency is achieved under a combination of element-specific kernels (including new quadrature-free operators for the pyramid), multi-rate timestepping, and acceleration using Graphics Processing Units.