[peterh]

Hello everybody,

I'm quite new to OpenFoam, and i was trying to test the k-omega-SST turbulence model in OF 1.4, and i got some errors. I would like to check back with you guys if I did the right things.

I'm running a 2D case on a "elbow"-tube geometry (like this: _| , hope you understand) with the simpleFoam-solver.

The following errors occurred:

1. The solver needed a "omega" file.
-> I made a copy of the "k" file, replacing the k with omega, changed the dimensions to [0 0 -1 0 0 0 0] and made an initial guess for omega via omega = sqrt(k) / L.

2. I got an error saying "keyword DomegaEff,omega not found in dictionary laplacianSchemes" or something like that.
-> I inserted the line " laplacian(DomegaEff,omega) Gauss linear corrected;" in the "fvSchemes" file

After this, the case was calculated without errors.
Now: Is what i did the right way to do this, and is this from a mathematical/physical view correct??

Strange thing: I wanted to copy-paste the laplacian-error in this thread, so i commented the "laplacian..." line out of fvSchemes, but the solver runs without problems, i cannot reproduce this error...

Keep up the good work!

Peter

[fra76]

Hello!
I'm making some tests with the new kOmegaSST model in OF 1.4, and it seems to work quite well.
However, I couldn't find anywhere if there is a transition model implemented or not.
Can someone clarifing the question?

Thanks,
Francesco

[rolando]

There is no transition model implemented in the kOmegaSST model.

Rolando

[fra76]

Thanks a lot for the quick answer!
Francesco

[mighelone]

I've a question about k-omega SST and more generally about Low-Re turbulence model!
These models do not use the wall function approach on the contrary of general k-epsilon model.

With wall function models I have to set the wall boundary conditions for k and epsilon imposing zero gradient.
It is the same for k-omega SST and low-Re models?

Another question is : have I to define the wallFunctionCoeff in turbulenceProperties dictionary? If I don't define this keyword I obtain an error.

Thanks
Michele

[jdk]

Hi, I have a question regarding the changes one need to make in the fvSchemes and fcSolution files to get the kOmegaSST turbulence model to work in version OF 1.4.1. I follow the guidelines that Peter Heering laid out in the first message of this thread, and added the extra entries/changes to make the case run. However, these changes didn't show up in FoamX and if I saved the case in FoamX I would loose the changes I had allready made by hand in the 2 files. How can I remedy this problem?

[andrewburns]

I'm playing around with the k-omega SST model right now and I've had the same thing happen. If you switch to K-omegaSST in foamX it won't make the correct files/changes to files. If you make the changes yourself and then re-open foamX it complains about not being able to find things to do with epsilon (because I got rid of them). I haven't managed to lose the changes I made yet by opening the case in foamx, just had it complain.

[jdk]

Hi Andrew,
Have you tried to save your case in FoamX? I consistently loose all the changes I make by hand in fvSchemes and fvSolution if I save the case in FoamX. I guess this problem is connected to the fact that changes doesn't show up in FoamX when I load the case. For example, I have added an initial omega field by copying and renaming the .../0/k file to .../0/omega and made some relevant changes inside the file also. This field doesn't show up in the FoamX case browser but I can run the case without problems. My guess is that I have to modify some configuration files for FoamX. Maybe in "$HOME/OpenFOAM/OpenFOAM-1.4.1/applications/solvers/incompressible/simpleFoam/Fo amX/"? But right now I wouldn't know what to change?