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Divergence in amg solver while using second order scheme |
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November 2, 2012, 12:51 |
Divergence in amg solver while using second order scheme
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#1 |
New Member
rajkumar
Join Date: Oct 2012
Posts: 3
Rep Power: 13 |
Hi all
Iam doing a transient combustion analysis with partially premixed model and compressible case. I am using k-e realisable turbulence model. While running the case with all methods set to first order i got good convergence of results. However when i changed to second order schemes i get the amg solver divergence . Kindly suggest me what could be the problem |
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November 2, 2012, 13:34 |
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#2 |
Member
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Second order Schemes got less relaxation to the high gradients because the adjacent cells involved are more( j+2,J-2), thus the high gradients of parameters could result in a bad behavior. Try to decrease your RFs and check the Green-Gause node based in solver panel.
Regards. |
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November 2, 2012, 23:39 |
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#3 |
New Member
rajkumar
Join Date: Oct 2012
Posts: 3
Rep Power: 13 |
Hi Thanks for the reply
I have reduced the relaxation factors and the solver is running. But i would like to ask one thing whether by reducinf the RF's does it alter the final results? |
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November 3, 2012, 01:10 |
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#4 |
Senior Member
Join Date: Mar 2011
Location: Germany
Posts: 552
Rep Power: 20 |
No your final solution will remain unaltered however your convergence time will be more with the reduced values of RF's
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