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-   -   divDevReff? (http://www.cfd-online.com/Forums/openfoam-programming-development/123018-divdevreff.html)

sharonyue September 2, 2013 23:08

divDevReff?
 
1 Attachment(s)
Hi guys,

In KEpsilon.C we have:

Code:

tmp<fvVectorMatrix> kEpsilon::divDevReff(volVectorField& U) const
{
    return
    (
      - fvm::laplacian(nuEff(), U)
      - fvc::div(nuEff()*dev(T(fvc::grad(U))))
    );
}

According to my equation, see the image attached.

Should it be:
Code:

return
    (
      - fvm::laplacian(nuEff(), U)
      - fvc::div(nuEff()*T(fvc::grad(U)))
    );

?

GerhardHolzinger September 5, 2013 04:06

The math behind
 
1 Attachment(s)
Take a look at the equations I attached.

sharonyue September 5, 2013 09:15

Quote:

Originally Posted by GerhardHolzinger (Post 450006)
Take a look at the equations I attached.

Long time no see Gernard, Excellent!!!
Thanks so much:D:D

sharonyue September 8, 2013 23:30

Woo, but if these two terms are the same? Why should we use the dev instead of neglecting it?

GerhardHolzinger September 9, 2013 02:28

It two terms are equal you are neglecting nothing.

There may be numerical or other reasons for doing so.


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