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Old   September 30, 2013, 16:44
Default numeric schemes
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Tobias Holzmann
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Dear all,

what whould you use for U/k/epsilon etc. . . .

Code:
BICCG
GAMG
PBiCG
smoothSolver
Thanks in advance,
Tobi
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Old   October 1, 2013, 03:49
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Anton Kidess
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The first three solvers should always outperform smoothSolver. GAMG should outperform CG methods when not limited by communication (this is especially true for the pressure equation). If you're in doubt, just run a couple fixed timesteps with each of the solvers and you will very quickly find out where you can save time.

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Dear all,

what whould you use for U/k/epsilon etc. . . .

Code:
BICCG
GAMG
PBiCG
smoothSolver
Thanks in advance,
Tobi
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Old   October 1, 2013, 04:19
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As akidess already said, for p a good choice should be GAMG, for other fields I usually use PBiCG.

BICCG shouldn't be used any more:
Quote:
Diagonal incomplete LU preconditioned BiCG solver derived from the general preconditioned BiCG solver PBiCG but with the choice of preconditioner pre-selected. Deprecated:This solver is present for backward-compatibility and the PBiCG solver should be used instead. (deprecated Apr 2008)
source: http://foam.sourceforge.net/docs/cpp/a00098.html
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Old   October 7, 2013, 08:47
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Mohsen KiaMansouri
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Dear Foamers
Have a look at the following references for more details:

P. K. Khosla, and S. G. Rubin, “A diagonally dominant second-order accurate implicit scheme”, Computers and Fluids, 2:207-209, 1974.

M. R. Hestens, and E. L. Steifel, “Method of conjugate gradients for solving
linear systems”, Journal of Research, 29:409-436, 1952.

D. A. H. Jacobs, “Preconditioned Conjugate Gradient methods for solving
systems of algebraic equations”, Central Electricity Research Laboratories
Report, RD/L/N193/80, 1980.

H. A. Van Der Vorst, “Bi-CGSTAB: A fast and smoothly converging variant of Bi-CG for the solution of nonsymmetric linear systems”, SIAM J. Scientific Computing, 13(2):631-644, 1992.
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Old   October 8, 2013, 23:52
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PBiCG is good.
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