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GAMG solver in OpenFOAM 14

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Old   May 29, 2007, 13:51
Default In OF 1.3, we used the followi
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Srinath Madhavan (a.k.a pUl|)
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In OF 1.3, we used the following syntax in the fvSolution file:

p AMG 1e-06 0 25;

If I were to translate the same into OF 1.4, I would expect the following syntax:

p GAMG
{
tolerance 1e-06;
relTol 0;
nCellsInCoarsestLevel 25;

};

My question is whether we need to specify nPreSweeps, nPostSweeps and nFinestSweeps? Also, can someone explain the use of mergeLevels?

Also what smoothers are available?

Many thanks!
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Old   May 31, 2007, 11:55
Default mergeLevels is the number of m
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Eugene de Villiers
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mergeLevels is the number of merge operations to do between grid levels. mergeLevel 1 is equivalent to what is hard coded in AMG and is what I normally use.

agglomerator faceAreaPair; seems to work best

smoother options are: GaussSeidel, DIC and DICGausSeidel. GausSeidel seems to work best, but DICGaussSeidel might be better for more difficult problems. It is more expensive though.

nPreSweeps, nPostSweeps, nFinestSweeps: I use 0,2,2 and this should work for most problems. Feel free to experiment though.
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Old   May 31, 2007, 15:28
Default Many thanks for that clear exp
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Srinath Madhavan (a.k.a pUl|)
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Many thanks for that clear explanation Eugene!
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