Understanding k-omega SST model source code
I'm currently working on my master's thesis and using OpenFOAM 1.5 for aerodynamics calculations (incompressible, subsonic). I was writing down equations used by the K-omega SST turbulence model implemented in OF1.5, when I run into some difficulties. I hope someone could shed some light into this.
The source code of the model clearly states that the implementation is based on this paper:
Menter, F., Esch, T.
"Elements of Industrial Heat Transfer Prediction"
16th Brazilian Congress of Mechanical Engineering (COBEM),
I do not have that, but instead I have looked at the following sources:
 Menter SST Two-Equation Model from 2003 http://turbmodels.larc.nasa.gov/sst.html
 Ten Years of Industrial Experience with the SST Turbulence Model http://cfd.mace.manchester.ac.uk/flo...nter-SST-paper
 K-omega SST in OpenFOAM-1.5 http://www.tfd.chalmers.se/~hani/kur...lenceModel.pdf
My questions are:
1) In the source code KOmegaSST.C on line 397 nut is defined as:
nut_ = a1_*k_/max(a1_*omega_, F2()*sqrt(S2));
and on line 344:
S2 = magSqr(symm(fvc::grad(U_)));
However on line 363 in the omega-equation, the term gamma*S^2 is stated as
Now where does that factor 2 between gamma and S^2 come from?
In Ref  it is found that for the 2003 model in fact this formulation would
be correct (S=sqrt(2*S_ij*S_ij)), if this was used then the nut -equation is
inconsistent as the sqrt(2) factor is missing!
2) The G-term defined in line 345 is
As far as I understand it is not defined like this in Refs [1,2,3,4]. How is this
done in the code when G-term is used in the same way as in Refs?
I suppose there is nothing wrong with the code, and just some programming
gimmick is used that I don't understand, but it would be much appreciated if
someone could help me to see how the model was implemented.
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