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-   -   lowReOneEqEddy sgsModel (http://www.cfd-online.com/Forums/openfoam-solving/68080-lowreoneeqeddy-sgsmodel.html)

cosimobianchini September 5, 2009 13:49

lowReOneEqEddy sgsModel
 
Hi foamers,
has any of you ever worked with lowReOneEqEddy?

I could see from the comments in the header file that this model implements
nuSgs this way:

nuSgsHiRe = ck*sqrt(k)*delta;
nuSgs = (nu/beta)*(1 - exp(-beta*nuSgsHiRe/nu));

What is this correction supposed to be for?
Is it supposed to act as a damping function for near wall treatment or the lowRe simply stands for low free stream velocity, and the exponential function is just used to limit the maximum nuSgs to 100 times the laminar viscosity?
Does anybody have a reference, to share or to suggest, for this model?

Anyhow looking at the source code, there appears to be an incosistency between the comments and the code itself:

void lowReOneEqEddy::updateSubGridScaleFields()
{
// High Re eddy viscosity
muSgs_ = ck_*rho()*sqrt(k_)*delta();

// low Re no corrected eddy viscosity
muSgs_ -= (mu()/beta_)*(scalar(1) - exp(-beta_*muSgs_/mu()));
muSgs_.correctBoundaryConditions();

alphaSgs_ = muSgs_/Prt_;
alphaSgs_.correctBoundaryConditions();
}

In particular shouldn't the -= operator be just = ?

Thanks a lot for sharing any comment,
Cosimo


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