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calculate epsilon from RANS k-Omega simulation

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Old   June 20, 2013, 06:07
Default calculate epsilon from RANS k-Omega simulation
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Hi FOAMers,

in order to get the epsilon value from a RANS simulation (kOmega, kOmegaSST respectively) I was searching the source code. This is what I've found in kOmegaSST.H:

00250         //- Return the turbulence kinetic energy dissipation rate
 00251         virtual tmp<volScalarField> epsilon() const
 00252         {
 00253             return tmp<volScalarField>
 00254             (
 00255                 new volScalarField
 00256                 (
 00257                     IOobject
 00258                     (
 00259                         "epsilon",
 00260                         mesh_.time().timeName(),
 00261                         mesh_
 00262                     ),
 00263                     betaStar_*k_*omega_,
 00264                     omega_.boundaryField().types()
 00265                 )
 00266             );
 00267         }
My question: How can I run this section to get epsilon (for e.g. in case of the reynoldsstresstensor it's just the command R)

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Old   June 27, 2013, 10:55
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I don't know if this is the best way to get the epsilon value but it works!

1. create the directory ~/Openfoam/$USER-2.1.x/utilities/postProcessing/turbulence/

2. copy the attached files into.

3. run the command "wmake" from the epsilon directory

This will create the folders platforms/.../bin in the ~/Openfoam/$USER-2.1.x/ directory and compiles the epsilon.C file. The executive "epsilon" is created there and can be called by "epsilon" from any case directory.

Note: This should work for kOmega as well as for kOmegaSST. While the difference is simply a change of constants:
kOmega: epsilon=Cmu*k*omega
kOmegaSST: epsilon=betaStar*k*omega
Which is normally the same value: betaStar=Cmu=0.09
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