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-   -   interFoam Ueqn (http://www.cfd-online.com/Forums/openfoam/82640-interfoam-ueqn.html)

alvin11 December 1, 2010 09:50

interFoam Ueqn
 
the LHS of UEqn is as follows,
fvVectorMatrix UEqn
(
fvm::ddt(rho, U)
+ fvm::div(rhoPhi, U)
- fvm::laplacian(muEff, U)
- (fvc::grad(U) & fvc::grad(muEff))
);

I want to know the physical meaning of the last term,
(fvc::grad(U) & fvc::grad(muEff)) and wher it come form,

santiagomarquezd December 1, 2010 17:44

Hi Alvin, this term is due spatial variation of muEff. From the Cauchy equation you have for the viscous term div & [muEff*grad(U)], since muEff is not a constant, using the chain rule: muEff*laplacian(U)+grad(muEff)&U.

Regards.

alvin11 December 2, 2010 02:28

Thanks,very helpful


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