Numerical Analysis Seminar Talk, October 2, 1996

Speaker: Professor David Darmofal, Department of Aerospace, Texas A&M University
Title: Multigrid Methods for Convection-dominated Flows
Time: 4:00pm, Wednesday, October 2, 1996
Place: 503 Blocker

Abstract:

In this seminar, we will discuss recent advances in preconditioning techniques for hyperbolic systems with particular emphasis on their utility in multigrid methods. Our specific examples will be based on the two-dimensional Euler equations, and the focus of this talk will be local block preconditioners. In particular, we will study two classes of local preconditioners: the discrete-based block Jacobi preconditioner, and the continuum-based based local preconditioners of Turkel and van Leer. Analysis of the low frequency wave propagation characteristics of the Euler and preconditioned Euler equations will be discussed. In particular, we will show that the block Jacobi preconditioner does not effectively reduce the spread of characteristic speeds especially for low Mach number flows while the continuum-based local preconditioners provide optimal wave speed equalization at all Mach numbers. The performance of these preconditioners is compared for several tests cases within a multigrid algorithm showing that the continuum-based preconditioners result in much more effective multigrid algorithms than the discrete block Jacobi preconditioners.

Numerical Analysis Seminars

Last revised: 09/26/96 By: Tong.Sun@math.tamu.edu