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-   -   One question about the discretization of governing equation in OpenFOAM (http://www.cfd-online.com/Forums/openfoam-solving/95370-one-question-about-discretization-governing-equation-openfoam.html)

JinBiao December 14, 2011 22:05

One question about the discretization of governing equation in OpenFOAM
 
I found there is an extra term in some solvers. I am not sure about the reason. For example in the TEqn.H of buoyantBoussinesqSimpleFoam. The scalar matrix is constructed via

fvScalarMatrix TEqn
(
fvm::div(phi, T)
- fvm::Sp(fvc::div(phi), T)
- fvm::laplacian(kappaEff, T)
);

The second term seems not necessary here. And it also make the discretization become nonconservative. I wonder why this is necessary. In contrast in the UEqn.H in the same solver

tmp<fvVectorMatrix> UEqn
(
fvm::div(phi, U)
+ turbulence->divDevReff(U)
);

Such term does not appear. Can anyone explain why we need this?

Thanks a lot.

Best Regards,

Tarak December 30, 2011 04:49

Hii,

The line is added to have values of T bounded in the algorithms like SIMPLE where we have partial convergence of pressure. Check this: http://www.cfd-online.com/Forums/ope...silon-eqn.html


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