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Energy equation in OpenFoam

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Old   June 23, 2014, 21:35
Default Energy equation in OpenFoam
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Kan
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Dear OpenFoamer,

I have a question regarding the energy equation in rhoSimpleFoam. see code:

fvm::div(phi, h)
- fvm::Sp(fvc::div(phi), h)
- fvm::laplacian(turbulence->alphaEff(), h)
==
- fvc::div(phi, 0.5*magSqr(U), "div(phi,K)")

I think this energy equation written in enthalpy has missed viscous related term, is that right? because I use this solver to simulate a shear driven flow, but the temperature increase is small compared to experiment results.

If I am right, how can I add this viscous related term to my energy equation?

Thank you!
Kan
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Old   June 23, 2014, 23:34
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Kan
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I've included this stresses term to energy equation, see below:

(1)
volTensorField gradU = fvc::grad(Urel);
(2)
volTensorField tauEff = turbulence->muEff()*(gradU + gradU.T()) + turbulence->muEff()*dev2(T(fvc::grad(Urel)));
(3)
- (tauEff && gradU)

The second point is the code for stresses term in energy equation. I saw this from #18

http://www.cfd-online.com/Forums/ope...-equation.html

I don't quite understand this code: turbulence->muEff()*dev2(T(fvc::grad(Urel)))? can anyone explain this?

Thank you!
Kan
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Old   June 24, 2014, 02:40
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volTensorField tauEff = turbulence->muEff()*(gradU + gradU.T()) + turbulence->muEff()*dev2(T(fvc::grad(Urel)))
this term is for stress term.

I am just curious that why the compressible solver in OpenFoam didn't consider this term in energy equation?
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