divDevReff?

sharonyue · September 3, 2013, 00:08

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, 05:06

Take a look at the equations I attached.

sharonyue · September 5, 2013, 10:15

Quote:

Originally Posted by GerhardHolzinger

Take a look at the equations I attached.

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

sharonyue · September 9, 2013, 00:30

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

GerhardHolzinger · September 9, 2013, 03:28

It two terms are equal you are neglecting nothing.

There may be numerical or other reasons for doing so.

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September 9, 2013, 00:30		#4
sharonyue Senior Member Dongyue Li Join Date: Jun 2012 Location: Beijing, China Posts: 848 Rep Power: 18	Woo, but if these two terms are the same? Why should we use the dev instead of neglecting it?

September 9, 2013, 03:28		#5
GerhardHolzinger Senior Member Gerhard Holzinger Join Date: Feb 2012 Location: Austria Posts: 342 Rep Power: 28	It two terms are equal you are neglecting nothing. There may be numerical or other reasons for doing so.