GAMG vs. PCG in fvSolution
hi foamers,
i'm working with two domains of exactly same geometry and case configurations. one domain has 150000 cells, the other about 6*10^6 cells. in the coarse domain case the GAMG solver needs about 30 iterations for one timestep (nCellsInCoarsestLevel = 1000). on the other hand, if i choose PCG the calculation needs 230 iterations. in the fine domain case it's the opposite: PCG needs about 1000 iterations but GAMG does need more (maxIter limitation at 1500, various nCellsInCoarsestLevel). what's your experience with GAMG? any tips what i could try? best regards grandgo |
Hi,
Did you find any answer? I am solving a external flow simulation. When i increase the number of layers and decrease the min thickness close to 9.6e-06,in a GAMG solver the iterations reach close to 1000 and crashes but on the other hand PCG works very well. Is there any reason behind. Thanks, Antony |
Hi,
Thanks for opening this topic. I have two suggestions: 1) Some people here on the forum say nCellsInCoarsestLevel shouldn't be above 50. On my cases I always make sure to make a "nCellsInCoarsestLevel-study". 2) I think your post would be even more meaningful if you would tell us the calculation time/iteration or per timestep. The number of iterations alone is not so meaningful from my point of view. Best regards, Kate |
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