High-Order Explicit Local Time-Stepping Methods For Wave Propagation

Vortrag von Prof. Dr. Marcus Grote

Sprecher eingeladen von: Prof. Dr. Stefan Sauter

Datum: 29.11.17  Zeit: 16.15 - 17.15  Raum: ETH HG E 1.2

In the presence of complex geometry, adaptivity and mesh refinement are certainly key for the efficient numerical simulation of wave phenomena. Locally refined meshes, however, impose severe stability constraints on any explicit time-marching scheme, where the maximal time-step allowed by the CFL condition is dictated by the smallest elements in the mesh. When mesh refinement is restricted to a small subregion, the use of implicit methods, or a very small time-step in the entire computational domain, are very high a price to pay. Explicit local time-stepping schemes (LTS) overcome the bottleneck due to a few small elements by using smaller time-steps precisely where the smallest elements in the mesh are located. When combined with a finite element discretization in space with an essentially diagonal mass matrix, the resulting time-marching schemes are fully explicit and thus inherently parallel.