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Old   December 10, 2012, 01:00
Default SA Model Clarification
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KGN
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I am trying to simulate compressible flow through an air intake.

I used SA model for turbulence. I defined "nuTilda" and "mut". When i run the problem, i get the following warning..

Then i define "k" and "epsilon". Even though i get the same warning.

What actually does it mean.

FOAM Warning :
From function tmp<volScalarField> SpalartAllmaras::k() const
in file SpalartAllmaras/SpalartAllmaras.C at line 262
Turbulence kinetic energy not defined for Spalart-Allmaras model. Returning zero field

Also when i tried to calculate the "yPlus". it asks for "nut". why?

Cheers
KGN
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Old   December 11, 2012, 08:03
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Any reply ?
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Old   July 31, 2014, 05:31
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yossi
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Hi,

Have you found a solution?
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Old   July 31, 2014, 07:39
Default mutkWallFunction or mutUWallFunction
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Fabian Roesler
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Hi

Maybe I can help with this. Spalart Allmaras is a one equation turbulence model. It is not using turbulent kinetic energy k and a second variable like kEpsilon or kOmega models. Thus, the wall function for nut / mut have to be nutUWallFunction / mutUWallFunction instead of nutkWallFunction / mutkWallFunction for two equation models. So briefly:

Quote:
Spalart Allmaras --> one equation model (nuTilda)
nutUWallFunction (incompressible flow)
mutUWallFunction (compressible flow)

kOmega / kEpsilon --> two equation model (k and either epsilon or omega)
nutkWallFunction (incompressible flow)
mutkWallFunction (compressible flow)
Hope it helps.

Cheers

Fabian
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Old   August 2, 2014, 05:46
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I see,

Thanks!
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