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Multirate Time Stepping for Accelerating Explicit High Order Discontinuous Galerkin Computations
| Content Provider | Semantic Scholar |
|---|---|
| Author | Seny, Bruno Lambrechts, Jonathan Remacle, Jacques E. Legat, Vincent |
| Copyright Year | 2010 |
| Abstract | The development of suitable and fast time integration methods for ocean modeling constitutes an important challenge. No single time-discretisation works well for all physical processes in a complex marine model, as different subsystems have widely different characteristics in terms of time scales, dynamic behaviour, and accuracy requirements. The primitive equations for ocean flows allow for the existence of phenomena exhibiting a wide spectrum of propagation speeds. Typically, external gravity waves propagate at 101 − 102 ms−1 and internal waves at a few meters per second, whereas advection is characterized by speeds ranging from 10−3 to 1 ms−1. We believe that building appropriate time stepping strategies for multi-scale computations will enable us to gain an order of magnitude. For instance, consider the case of a typical mesh of the Great Barrier Reef (GBR) made up of about 1 million triangles. Element sizes were determined in order to capture the relevant bathymetric and topographic features, and the associated hydrodynamic processes, such as eddies and tidal jets ( Lambrechts et al., 2008). Unstructured-mesh generation processes are complex and, even though it is possible to control average element sizes in specific regions of the domain, it is not the case for each element size. The smallest element is usually much more smaller than the criterion that was prescribed a priori. Typically, it is often possible that more than 99% of the elements have a size that is much more larger than the smallest element. So, if we apply a local Courant–Friedrichs–Lewy (CFL) condition, the global time step would be critically smaller than the one required for 99% of the elements. We propose a class of methods that use various time steps on different grid |
| File Format | PDF HTM / HTML |
| Alternate Webpage(s) | http://mseas.mit.edu/download/wgleslie/IMUM2010/IMUM_abstract_seny.pdf |
| Language | English |
| Access Restriction | Open |
| Content Type | Text |
| Resource Type | Article |
