[petsc-users] Pre-conditioner for parallel CFD simulation

[Denner, Fabian]

I solve fully implicit, incompressible DNS of low/moderate Reynolds number (Re = 1 - 1000) flows. The hexahedral meshes to test the code have an aspect ration of 1, the tetrahedral meshes are Voronoi-based, do not have high aspect ratios and a good quality. 
________________________________________
From: five9a2 at gmail.com [five9a2 at gmail.com] On Behalf Of Jed Brown [jed at 59A2.org]
Sent: 14 April 2011 18:28
To: PETSc users list
Cc: Denner, Fabian
Subject: Re: [petsc-users] Pre-conditioner for parallel CFD simulation

On Thu, Apr 14, 2011 at 19:20, Denner, Fabian <f.denner09 at imperial.ac.uk<mailto:f.denner09 at imperial.ac.uk>> wrote:
I have a question concerning pre-conditioner/solver pairs for CFD. I'm using the BiCGStab solver with a Jacobi pre-conditioner at present to perform parallel simulations of fluid flow on unstructured grids.

There are lots of methods for CFD. Maybe you could be more specific about what you're solving (laminar, RANS, LES, DNS; compressible?; fully implicit, v-p split implicit, explicit v/implicit p). The mesh quality is also relevant. Do you have aspect ratio 10^6 elements as for wall-resolved LES?

It works, however, for large meshes (>100k elements) the solver doesn't scale very well in terms of necessary iterations to reach a certain tolerance.
Does anybody have experience on which pre-conditioner works best for parallel CFD simulations using the BiCGStab solver? How is the convergence and stability of the multigrid solver compared to BiCGStab?

1/(\Delta x) iterations versus 1