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Strange behaviour when using LienCubicKE and NonlinearKEShih

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Old   March 6, 2013, 11:06
Default I am agree with you
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Akbar Mohammadi Ahmar
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Originally Posted by jkim View Post
Is there anyone who knows correct generation term for nonlinear turbulence model?

In all the nonlinear models in OpenFoam, the generation term looks like
G = nu_t * symm(grad(U)) && grad(U) - nonlinear_term (1)

I think the first term of G must be same as one in linear models.
In linear models such as kEpsilon,
G = nu_t * 2 * symm(grad(U)) && grad(U) (2)
= nu_t * 2 * magSqr(symm(gradU))

I can't understand why factor 2 is omitted in eq. (1).

If you know the reason or the correct generation for nonlinear turbulence model, please give your help to me.

Many thanks
************************************************** *
Hi jkim,
I agree with you , Because I work with nonlinear models for example quadratic Shih .
when that me use the first term of G (nu_t * symm(grad(U)) && grad(U)) result of solution
is uncorrect .
But , I run same model with G = nu_t * 2 * symm(grad(U)) && grad(U)- nonlinear_term that result is very good.
so, I think your opinion is correct.
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