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#1 |
Member
zakir
Join Date: Nov 2011
Posts: 44
Rep Power: 14 ![]() |
hello everyone
when i am reading the icoFoam.c,I feel confused with it. It said that "include 'readPISOcontrols.H'"and I found the file which defined the number like this: const int nCorr = pisoDict.lookupOrDefault<int>("nCorrectors", 1); const int nNonOrthCorr = pisoDict.lookupOrDefault<int>("nNonOrthogonalCorre ctors", 0); I think it doesn't fit very case. my question is how to decide the nCorr and nNonOrthCorr. Are there any relative theories about this? I have read jasak's phd, but I didn't find the answer. Thank you very much. Best Regards! zakir |
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#2 |
Senior Member
Nima Samkhaniani
Join Date: Sep 2009
Location: Tehran, Iran
Posts: 1,266
Blog Entries: 1
Rep Power: 24 ![]() |
whats your mean by "decide the nCorr and nNonOrthCorr" ?
you can define these values in your case directory at system/fvSolution lookupOrDefault : if you define a value in your fvSolution file then it chooses that value and if you dont define the value, solver considers it as default number which is 1 for nCorr and 0 for nNonOrthCorr. usually 2,3 times of corrections are usually enough for piso Algorithm so ( nCorr = 2, 3 ) but for non-orthogonality depends on your mesh and how much non orthogonal it is! |
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#3 |
Member
zakir
Join Date: Nov 2011
Posts: 44
Rep Power: 14 ![]() |
thanks to nima. I have make clearly about ncorr. I know that the non-orthogonality depends on my mesh,but I don't know what it means "how much non orthogonal it is".Could you please give me a detailed explaination about deciding the nNonOrthCorr on a non-orthogonal mesh?
thank you very much |
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#4 | |
Member
pooyan
Join Date: Nov 2011
Posts: 62
Rep Power: 14 ![]() |
Hi Nima,
I have a question from you. I am now solving cavity problem in 3D. for turbulence model, I selected RANS and k-epsilon. for wall function, I selected nutkwallfunction. However, I could not find the procedure (how the wall function is defined) used in this type of wall function. I would be grateful if you could tell me what specific wall function is used in nutkwallfunction. Thanks, Pooyan Quote:
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#5 | |
Senior Member
Nima Samkhaniani
Join Date: Sep 2009
Location: Tehran, Iran
Posts: 1,266
Blog Entries: 1
Rep Power: 24 ![]() |
Quote:
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#6 | |
Senior Member
Nima Samkhaniani
Join Date: Sep 2009
Location: Tehran, Iran
Posts: 1,266
Blog Entries: 1
Rep Power: 24 ![]() |
Quote:
please next time , open new thread or post ur question in related topic however for k-epsilon look at userguide page-41 or in brief: Code:
kappa = 0.5U*U* epsilon = C^0.75 kappa^1.5 / l C = 0.09 l = characteristic length |
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nnonorthcorr |
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