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February 9, 2011, 15:45 
Nonorthogonal correctors

#1 
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Johan Magnusson
Join Date: Oct 2010
Posts: 21
Rep Power: 8 
Okey, lets see how i should explain this. I have a mesh that is (according to my previous knowledge ok regarding orthogonality) but I still want to be sure that the solver dont make to large error on a different mesh, I need therefore an implementation of a nonorthogonal corrector.
Easiest seems to be to use the PISO or SIMPLE loop, which i read corrects for nonorthogonality (http://openfoamwiki.net/index.php/Th...hm_in_OpenFOAM, ... The steps 4 and 5 can be repeated for a prescribed number of time to correct for nonorthogonality. ) The strange thing is that inside the fvSchemes at the "laplacianSchemes": laplacianSchemes { default none; laplacian((****)),p) Gauss linear corrected; } There is something called "Gauss linear correced", which according to the UserGuide means "Explicit nonorthogonal correction". I know also that there are other choices. At the end this leads to my question; is this correction enough or do I have to implement some kind of PISO/SIMPLE loop for correction? It confuses me since it seems to occur some kind of correction already! 

February 10, 2011, 04:30 

#2 
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Gijsbert Wierink
Join Date: Mar 2009
Posts: 383
Rep Power: 11 
Hi Johan,
In fvSolutions you can actually define the number of (nonorthogonal) correctors, so it's probably separated from the schemes like that. in FvSolutions you might have something like Code:
PISO { nCorrectors 4; nNonOrthogonalCorrectors 2; pRefCell 0; pRefValue 0; }
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Regards, Gijs 

February 10, 2011, 09:27 

#3  
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Johan Magnusson
Join Date: Oct 2010
Posts: 21
Rep Power: 8 
Quote:


June 25, 2013, 08:43 

#4  
Senior Member
Join Date: Mar 2010
Location: Cape Town, SA
Posts: 156
Rep Power: 10 
Quote:
did you ever get an answer to this??? i am trying to understand the same thing, although there still doesnt seem to be much around in terms of an explanation ... best regards jonathan 

September 4, 2014, 08:35 

#5  
Senior Member

Quote:
I am also struck on to it. Did you find the answer for your query? 

September 7, 2014, 07:29 

#6 
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Julian Langowski
Join Date: May 2011
Location: Bremen, Germany
Posts: 91
Rep Power: 8 
Hi guys,
as I understand (and I hope, I do not tell you something wrong ): In fvSolution you define, that you want to use the PISO iteration, the amount of used iterations, ... In fvSchemes you have to define additionally, on which quantities or terms you want to apply the correction. So you have to define the nonOrthoCorrection in both files to properly work. Does this answer your question? Best regards Julian
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Tags 
corrected, nonorthogonality, orthogonality, piso, simple 
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