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-   -   Inclined Turbulent Flat Plate with Viscous Layer (https://www.cfd-online.com/Forums/openfoam-solving/163949-inclined-turbulent-flat-plate-viscous-layer.html)

Chanterz December 8, 2015 18:43

Inclined Turbulent Flat Plate with Viscous Layer
 
Greetings CFD Online goers,

I am new to OpenFOAM and CFD Online as well. I was wondering whether you could help me with my model of a turbulent flat plate in the k-Epsilon model, at an inclination to the flow direction. Also, there is a ground involved

I modelled my code off the pitzDaily tutorial, and previously modelled a non-inclined, flat plate with no viscous boundary layer, which worked!

I have added a viscous boundary layer to the ground and around the faces of the flat plate. It ran a couple of times for me using simpleFoam (so as not to over-complicate things too early on) with a viscous layer of thickness 0.1, 5 layers and a stretch factor of 1.2 . However, any changes I subsequently make to it, I get a floating point exception error, or 'stack overflow' ( - that's what it's called right?)

The unv file ran for me with simpleFoam without the viscous layer (y+ ~1800), and with the viscous layer described above (y = ~500). It is only when I change the coarseness of the mesh, or thickness of the boundary layer that it changes. I need to do this in order to bring the y+ value to be ~ 100. I have already implemented wall functions in my boundary conditions. I am using a GAMG mesh solver.

I have tried:
- changing my mesh from moderate to fine, and from moderate to coarse
- making the the viscous layer thicker
- slowing down the flow
- decreasing the time step from 1 to 0.001 (and smaller) and end time of 1, and even up to 100. I suspect this might be a Courant number problem...

I have made sure to make my patch headings the same after implementing ideasUnvToFoam in the boundary file.

checkMesh says the mesh is OK. If someone could check whether the orthogonality is within acceptable limits I would really appreciate it, as I'm not sure what it's supposed to be for the size of this mesh.

Any help would be greatly appreciated! :):cool:

If you would like to take up my case I might have to email you my .gz compression file, as I cannot upload due to security token problem.

Regards,
Jade




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