Research Colloquium — Thursday, November 13, 2008

"Advances in Wave Propagation with the Discontinuous Galerkin Method"

Tim Warburton
Department of Computational and Applied Mathematics
Rice University



A range of important features relating to the practical application of discontinuous Galerkin (DG) method for wave propagation will be discussed.

Recent investigations of the spectral properties of the discrete discontinuous Galerkin operators have revealed important connections with their continuous Galerkin counter parts. Theoretical and numerical results will be shown which demonstrate the correct asymptotic behavior of these methods and controls spurious solutions under mild assumptions.

Given the suitability of DG for solving Maxwell's equations and their ability to propagate waves over long distance, it is natural to seek effective boundary treatments for artificial radiation boundary conditions. A new family of far field boundary conditions will be introduced which gracefully transmit propagating and evanescent components out of the domain. These conditions are specifically formulated with DG discretizations in mind, however they are also relevant for a range of numerical methods.

There is an Achilles heel to high order discontinuous Galerkin methods when applied to conservation laws. The methods are typically constructed with polynomial field representations and unfortunately these suffer from excess maximum gradients near the edges of elements. I will describe a simple filtering process that allows us to reduce these anomalous gradients and provably yield a dramatic increase in the maximum allowable time step.

Finally, I will discuss the use of GPU hardware to accelerate computation for time-domain electromagnetics simulations.



Room: 126 Clements Hall
Coffee: 3:30 pm – 3:45 pm
Colloquium: 3:45 pm – 4:45 pm