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How to add temperature to icoFoam - correct?

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Old   July 30, 2012, 12:31
Default How to add temperature to icoFoam - correct?
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uli
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hi all

going through the tutorial http://openfoamwiki.net/index.php/Ho...ure_to_icoFoam

I did not completely understand the implementation of the energy equation.

Code:
            fvm::ddt(T)
             + fvm::div(phi, T)
             - fvm::laplacian(DT, T)
with phi = rho*U is equal to



whereas the energy equation is:



for a 2D flow not considerung the pressure terms, the dissipation function and with DT = thermal diffusivity = lambda/(rho * c_p)

Where is my mistake?

thank you
Uli
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Old   July 30, 2012, 14:00
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Greetings Uli,

I'm unable to answer your question, but I can make the following affirmation: that tutorial is basically an "how to copy-paste-modify code from scalarTransportFoam into icoFoam".
Here's a step-by-step explanation about scalarTransportFoam: http://openfoamwiki.net/index.php/ScalarTransportFoam

Best regards,
Bruno
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Old   July 31, 2012, 14:38
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uli
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hi Bruno, thanks for your response.

according to the ScalarTransportFoam the code is correct. Then in this case phi must be U and not rho * U.
I thought it's rho * U because here it is: http://www.openfoam.org/docs/user/fvSchemes.php (chapter 4.4.5)

Uli
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Old   July 31, 2012, 16:48
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Hi Uli,

Ah! Now I get it... this is so basic that even I can answer
  • Incompressible solvers assume constant rho, therefore only present in the viscosity.
  • Compressible solvers need "rho" as a field, therefore present in "rho * U".
Best regards,
Bruno
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