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June 26, 2019, 04:49 |
Linear solvers in OpenFOAM
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#1 |
New Member
Rahul
Join Date: Aug 2018
Posts: 6
Rep Power: 8 |
Hey guys, I am doing a project on OpenFOAM simulating external flow over an airfoil. I am confused with various linear solvers available to solve the problem in the fvSoultion file.
Can anyone explain me the difference between GAMG and PCG solver for pressure and when is each one of them used? |
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June 26, 2019, 12:34 |
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#2 |
Senior Member
Santiago Lopez Castano
Join Date: Nov 2012
Posts: 354
Rep Power: 15 |
Geometric Agglomerated MultiGrid
Parallel Conjugate Gradient easy enough to look on the interwebs |
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June 27, 2019, 03:45 |
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#3 |
Senior Member
Anton Kidess
Join Date: May 2009
Location: Germany
Posts: 1,377
Rep Power: 30 |
AFAIK -> PCG = Preconditioned Conjugate Gradient.
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June 27, 2019, 04:11 |
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#4 |
Senior Member
Santiago Lopez Castano
Join Date: Nov 2012
Posts: 354
Rep Power: 15 |
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June 30, 2019, 06:22 |
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#5 |
Senior Member
Ruiyan Chen
Join Date: Jul 2016
Location: Hangzhou, China
Posts: 162
Rep Power: 10 |
Interesting topic! You can check out the following link to get some insights.
https://www.openfoam.com/documentati...e-solvers.html Note there are GAMG preconditioners for PCG solvers, which is NOT the GAMG solver(belongs to the Multigrid solver catagory). By the way I remember some people stating that PCG solvers are better than GAMG for parallel computing. Is this true? What is the reason behind it? |
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July 2, 2019, 04:04 |
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#6 |
Senior Member
Anton Kidess
Join Date: May 2009
Location: Germany
Posts: 1,377
Rep Power: 30 |
More grids means more communication overhead. Not that important for small parallel simulations, but can become important for massive sims.
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*On twitter @akidTwit *Spend as much time formulating your questions as you expect people to spend on their answer. |
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July 2, 2019, 23:37 |
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#7 |
Senior Member
Ruiyan Chen
Join Date: Jul 2016
Location: Hangzhou, China
Posts: 162
Rep Power: 10 |
Thanks for the explanation!
Ruiyan |
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Tags |
gamg, linear solver, pcg |
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