Solver selection

ketanganatra0@yahoo.com · August 23, 2017, 05:01

Hi,
The valid asmmetric solvers are
PBiCG
smoothSolver
GAMG
The valid smmetric solvers are
PCG

If we chose different than the errorr message will appear and also for interchanging with symmetric and asymmetric

I want to knowthat for asymmetric matrix itself if we chose different for asymmetric from above three.

Will it affect the solution???

klausb · August 24, 2017, 13:59

Hello,

GAMG and smoothSolver can also be used for symmetric matrices.

Based on my experience with external flows, the choice is about speed and stability. PCG + PBiCG is the fastest combination for my cases but at high angles of attack, PBiCG might crash so I have to use another solver for those cases (actually OpenFoam tells me which one to use in the output/log file, when a simulation crashes).

To get exact results, adjust the fvSchemes for your type of simulations. It has a BIG impact on stability and helps to fine-tune results to match experimental results.

Klaus

August 23, 2017, 05:01	Solver selection	#1
ketanganatra0@yahoo.com New Member Ketan Ganatra Join Date: Aug 2017 Posts: 13 Rep Power: 8	Hi, The valid asmmetric solvers are PBiCG smoothSolver GAMG The valid smmetric solvers are PCG If we chose different than the errorr message will appear and also for interchanging with symmetric and asymmetric I want to knowthat for asymmetric matrix itself if we chose different for asymmetric from above three. Will it affect the solution???

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August 24, 2017, 13:59		#2
klausb Senior Member Klaus Join Date: Mar 2009 Posts: 250 Rep Power: 22	Hello, GAMG and smoothSolver can also be used for symmetric matrices. Based on my experience with external flows, the choice is about speed and stability. PCG + PBiCG is the fastest combination for my cases but at high angles of attack, PBiCG might crash so I have to use another solver for those cases (actually OpenFoam tells me which one to use in the output/log file, when a simulation crashes). To get exact results, adjust the fvSchemes for your type of simulations. It has a BIG impact on stability and helps to fine-tune results to match experimental results. Klaus