where does this term come from

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 June 12, 2013, 04:43 where does this term come from #1 Senior Member   Join Date: Mar 2010 Location: Cape Town, SA Posts: 156 Rep Power: 9 Hi everyone, I am solving a turbine case in OF2.1.1 using SRFSimpleFoam using kOmegaSST. I am having some bounding and convergence issues but am confused about a particular term in the divSchemes subdictionary in fvSchemes: Does anyone know which equation: Code: `div((nuEff*dev(T(grad(Urel))))) Gauss upwind; //linear;` comes from and why i cannot using Gauss upwind to discretize it - I get fatal read beyond EOF error if i dont use linear with it. thanks very much in advance jonathan

 June 12, 2013, 06:00 #2 Senior Member     Ehsan Join Date: Oct 2012 Location: Iran Posts: 2,209 Rep Power: 19 Hi Jonathan I had a problem like this with tauMC in rhoCentralFoam and Bruno said me that its a tensor field not a scalar or vector field that can use upwind schemes. if you can get more information or others its nice to share. __________________ Injustice Anywhere is a Threat for Justice Everywhere.Martin Luther King. To Be or Not To Be,Thats the Question! The Only Stupid Question Is the One that Goes Unasked.

 June 12, 2013, 08:51 from kOmegaSST turbulence model #3 Senior Member   Join Date: Mar 2010 Location: Cape Town, SA Posts: 156 Rep Power: 9 hi, so the term comes from the turbulence model (kOmegaSST): From kOmegaSST.H Code: ``` //- Return the source term for the momentum equation virtual tmp divDevReff(volVectorField& U) const;``` From kOmegaSST.C Code: ```tmp kOmegaSST::divDevReff(volVectorField& U) const { return ( - fvm::laplacian(nuEff(), U) - fvc::div(nuEff()*dev(T(fvc::grad(U)))) ); }``` As immortality says, this might be a tensor field, and so the standard divSchemes as per the UG do not apply, but i am still not 100% sure.

 June 16, 2013, 11:36 #4 Super Moderator   Bruno Santos Join Date: Mar 2009 Location: Lisbon, Portugal Posts: 9,679 Blog Entries: 39 Rep Power: 103 Greetings to all! @Jonathan: The post Ehsan was talking about is this one: error on linearUpwind - post #4. And yes, this is basically the same pattern of mathematics going on in this case. If you run the following command, you'll see that all tutorials in OpenFOAM use "Gauss linear" for this particular kind of div: Code: `find \$FOAM_TUTORIALS -name fvSchemes | xargs grep "T(grad(U"` Best regards, Bruno __________________ OpenFOAM: FAQ | Getting started Forum: How to get help, to post code/output and forum guide What am I doing/planning: blog/wiki Read this before sending me PM

June 17, 2013, 07:52
thanks
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Quote:
 Originally Posted by wyldckat Greetings to all! @Jonathan: The post Ehsan was talking about is this one: error on linearUpwind - post #4. And yes, this is basically the same pattern of mathematics going on in this case. If you run the following command, you'll see that all tutorials in OpenFOAM use "Gauss linear" for this particular kind of div: Code: `find \$FOAM_TUTORIALS -name fvSchemes | xargs grep "T(grad(U"` Best regards, Bruno
Hi Bruno,

Thanks very much - your help is much appreciated.

Best regards
Jon

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