# Non-orthogonal correctors

 User Name Remember Me Password
 Register Blogs Members List Search Today's Posts Mark Forums Read

 February 9, 2011, 14:45 Non-orthogonal correctors #1 New Member   Johan Magnusson Join Date: Oct 2010 Posts: 21 Rep Power: 14 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 non-orthogonal corrector. Easiest seems to be to use the PISO or SIMPLE loop, which i read corrects for non-orthogonality (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 non-orthogonality. ) 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 non-orthogonal 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, 03:30 #2 Senior Member   Gijsbert Wierink Join Date: Mar 2009 Posts: 383 Rep Power: 17 Hi Johan, In fvSolutions you can actually define the number of (non-orthogonal) 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; }``` __________________ Regards, Gijs

February 10, 2011, 08:27
#3
New Member

Johan Magnusson
Join Date: Oct 2010
Posts: 21
Rep Power: 14
Quote:
 Originally Posted by gwierink Hi Johan, In fvSolutions you can actually define the number of (non-orthogonal) 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; }```
Actually I dont have something like that, thats because I havent implemented any PISO/SIMPLE loop at this moment. If i refer to my question i asked more whats the difference between the correction that occurs in the PISO loop compared to the one that seems to occur in the "laplacianSchemes". If there arent any difference, is the PISO loop even necessary?

June 25, 2013, 08:43
#4
Senior Member

Join Date: Mar 2010
Location: Auckland, NZ
Posts: 168
Rep Power: 16
Quote:
 Originally Posted by magjohan Actually I dont have something like that, thats because I havent implemented any PISO/SIMPLE loop at this moment. If i refer to my question i asked more whats the difference between the correction that occurs in the PISO loop compared to the one that seems to occur in the "laplacianSchemes". If there arent any difference, is the PISO loop even necessary?
Hi Johan,

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

T. Chourushi
Join Date: Jul 2009
Posts: 321
Blog Entries: 1
Rep Power: 16
Quote:
 Originally Posted by magjohan Actually I dont have something like that, thats because I havent implemented any PISO/SIMPLE loop at this moment. If i refer to my question i asked more whats the difference between the correction that occurs in the PISO loop compared to the one that seems to occur in the "laplacianSchemes". If there arent any difference, is the PISO loop even necessary?
Good Question
I am also struck on to it. Did you find the answer for your query?

 September 7, 2014, 07:29 #6 Member   Julian Langowski Join Date: May 2011 Location: Bremen, Germany Posts: 91 Rep Power: 13 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 __________________ πάντα ῥεῖ - Heraclitus

 Tags corrected, non-orthogonality, orthogonality, piso, simple

 Thread Tools Search this Thread Search this Thread: Advanced Search Display Modes Linear Mode

 Posting Rules You may not post new threads You may not post replies You may not post attachments You may not edit your posts BB code is On Smilies are On [IMG] code is On HTML code is OffTrackbacks are Off Pingbacks are On Refbacks are On Forum Rules

 Similar Threads Thread Thread Starter Forum Replies Last Post vasu Main CFD Forum 8 October 28, 2015 15:20 ivanbuz ANSYS Meshing & Geometry 8 October 21, 2009 03:41 kassiotis OpenFOAM Running, Solving & CFD 6 May 15, 2008 06:07 vvqf OpenFOAM Running, Solving & CFD 1 March 22, 2006 05:21 Rudolf Pfeiffer Main CFD Forum 6 December 10, 1998 10:20

All times are GMT -4. The time now is 17:21.

 Contact Us - CFD Online - Privacy Statement - Top