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.
Original language | English |
---|---|
Title of host publication | ECCOMAS Congress 2016 - Proceedings of the 7th European Congress on Computational Methods in Applied Sciences and Engineering |
Publisher | National Technical University of Athens |
Pages | 2648-2663 |
Number of pages | 16 |
Volume | 2 |
ISBN (Electronic) | 9786188284401 |
Publication status | Published - 2016 |
Event | 7th European Congress on Computational Methods in Applied Sciences and Engineering, ECCOMAS Congress 2016 - Crete, Greece Duration: 2016 Jun 5 → 2016 Jun 10 |
Conference
Conference | 7th European Congress on Computational Methods in Applied Sciences and Engineering, ECCOMAS Congress 2016 |
---|---|
Country/Territory | Greece |
City | Crete |
Period | 2016/06/05 → 2016/06/10 |
Subject classification (UKÄ)
- Mathematics
Free keywords
- Multigrid
- Unsteady flows