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Old   December 14, 2011, 22:05
Default One question about the discretization of governing equation in OpenFOAM
Jinbiao Xiong
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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,
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Old   December 30, 2011, 04:49
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The line is added to have values of T bounded in the algorithms like SIMPLE where we have partial convergence of pressure. Check this:
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