[student666]

Hi all,

I'm trying to solve the following case study using OpenFOAM 2.3.1; it is an incompressible, steady state turbulent internal flow inside a bended pipe (simpleFoam). Here's the paper:
http://prod.sandia.gov/techlib/acces...004/043467.pdf
I chose to use this case to better understand turbulence modelling.

I managed to prepare the boundary layers according to what is written on the paper: first layer 0,15mm to the wall and by looking at the pictures, I also added 4/5 layers (1,2 expansion factor).

I chose to use the k-omega turbulence model for the calculation; the reason is because using the RNG-kEpsilon model (or standard kE), OF crashes at the beginning of each calculation.
Can't understand why; I also tried to run the case as laminar in the beginning, and then switching to turbulence, but every time it crashes. (Why?)

Initial conditions as for paper, I only set for the pressure value to 0Pa at outlet, and to 0,1Pa for the internal field.
I get a solution converged in about (monitoring mass-flow difference between inlet & outlet) 1800 iterations.
Anyway when I plot (in para-view) the 45° section on the bend, I'm not able to see any secondary (inertial) eddy as described in the paper (see fig.5).
Even value for p to the wall seems different: I got about 9000Pa (p*rho) instead of 100000Pa (see fig.6)

I can't really understand if my calculation is totally wrong and how should I check for mistakes, or simply it's a post-processing visualization problem.

Can someone help me?

Thanks a lot.

Michele

PS: in the tar file there's the 1800 time folder. If you want to run the case, you should:
1 - import the mesh from unv file
2 – using surfaceToPtach constant/triSurface/inlet.stl & surfaceToPtach constant/triSurface/outlet.stl to generate patches
3 - correct the boundary file
4 - run the case