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Turbulent frequency equation for compressible kOmegaSST turbulence model

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Old   August 31, 2013, 11:36
Default Turbulent frequency equation for compressible kOmegaSST turbulence model
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Bojan Sekutkovski
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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!
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Old   September 6, 2013, 07:45
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Joachim Herb
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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
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compressible komegasst, komegasst, omega, omega equation


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