A STUDY of multigrid smoothers used in compressible CFD based on the convection diffusion equation

Research output: Chapter in Book/Report/Conference proceedingPaper in conference proceeding

Abstract

We look at multigrid methods for unsteady viscous compressible flows. We specifically target smoothers that can be used in parallel and without computation of a Jacobian, which are particlarly attractive candidates in the context of Discontinuous Galerkin discretizations. In CFD, a plethora of nonlinear smoothers have been suggested which are hard to analyze. Our methodology is to use a linear model problem, here the convection diffusion equation, to be able to classify and compare smoothers better. Specifically, we consider explicit and implicit pseudo time iterations, GMRES as a smoother, SGS and implicit line smoothers. We relate GMRES to explicit Runge-Kutta smoothers, identify implicit line smoothers as Block Jacobi and analyze the potential of implicit pseudo time iterations. Finally, we discuss the relation between methods for steady and unsteady flows. Numerical results show that GMRES is a very attractive smoother in this context.

Details

Authors
Organisations
External organisations
  • Uppsala University
  • Stanford University
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Mathematics

Keywords

  • Multigrid, Unsteady flows
Original languageEnglish
Title of host publicationECCOMAS Congress 2016 - Proceedings of the 7th European Congress on Computational Methods in Applied Sciences and Engineering
PublisherNational Technical University of Athens
Pages2648-2663
Number of pages16
Volume2
ISBN (Electronic)9786188284401
Publication statusPublished - 2016
Publication categoryResearch
Peer-reviewedYes
Event7th European Congress on Computational Methods in Applied Sciences and Engineering, ECCOMAS Congress 2016 - Crete, Greece
Duration: 2016 Jun 52016 Jun 10

Conference

Conference7th European Congress on Computational Methods in Applied Sciences and Engineering, ECCOMAS Congress 2016
CountryGreece
CityCrete
Period2016/06/052016/06/10