Turbulent frequency equation for compressible kOmegaSST turbulence model
 

Hi everybody,

I have one question that concerns turbulent frequency equation in compressible kOmegaSST equation (I mean "omega equation")...
There is the definition of SuSP term in Programmers Guide: SuSp(rho,phi) = rho*phi

In turbulent frequency equation:

fvm::SuSp
(
rho_*(F1 - scalar(1))*CDkOmega/omega_,
omega_
)

which (by the programmers guide) means: (rho_*(F1 - scalar(1))*CDkOmega/omega_)*omega_

My question:

Why don't we simply write: rho_*(F1 - scalar(1))*CDkOmega ?


Regards!

I guess this is part of the numeric magic of OpenFOAM:
fvm::SuSp can be used to either add a source term explicitly or implicitly to an equation depending on the sign of the factor. This can improve the stability by increasing the diagonal dominance of the matrix.

See for example here: http://www.foamcfd.org/Nabla/guides/...x14-410002.4.9