[Polli]

I use a modified steadycompressibleMRFFoam out of OpenFOAM extend 3.1 and combined it with the coalCombustionCase to fill in the particle movement into the steadycompressibleMRFFoam. The simulation has a problem while solving the particle cloud. It does not crash and stops but the simulation never ends solving the cloud and begins to hang. There is no error message, it only take more than days for one iteration at the particles. Normally it takes 2 seconds to solve the cloud. There are no problem with the flow field, i insert the particles in the stady state flow filed.
I tried many different things, like reducing the timestep, meshing the surface more exactly and things like that.
Do anybody know a possible solution for this problem?

[Chrisi1984]

Hi Polly,

are you using "rebound" as wall interaction? In case you do so, the reason might be some bad quality in the mesh near to the wall.

For lagrangian simulations the mesh check should include an additional option:

checkMesh -allGeometry

Check the result from that analysis regarding "face tet" errors. Those "face tet" errors might be the reason for your "endless loop".

Kind regards
Chrisi

[Polli]

Thank you for your input! I will check this. But one question, in wich line can i see if the face tet is ok or not. In the checkMesh - allGeometry i cant find a output which says face tet ok or not

[Chrisi1984]

Hello,

this is a part of the output of checkMesh -allGemetry

Checking geometry...
Overall domain bounding box (-0.0992995958 -1.00600017 -0.0992995271) (0.0992943162 0.205000025 0.0992996263)
Mesh (non-empty, non-wedge) directions (1 1 1)
Mesh (non-empty) directions (1 1 1)
Boundary openness (5.29574358e-17 -5.49843007e-17 1.75436041e-16) OK.
Max cell openness = 3.17555515e-16 OK.
Max aspect ratio = 9.68193754 OK.
Minumum face area = 3.52951045e-08. Maximum face area = 2.4132503e-05. Face area magnitudes OK.
Min volume = 6.03259587e-12. Max volume = 7.03459743e-08. Total volume = 0.0126674936. Cell volumes OK.
Mesh non-orthogonality Max: 74.3872277 average: 15.458555
*Number of severely non-orthogonal faces: 1.
Non-orthogonality check OK.
<<Writing 1 non-orthogonal faces to set nonOrthoFaces
Face pyramids OK.
Max skewness = 0.961890176 OK.
Coupled point location match (average 0) OK.
Face tets OK.
Min/max edge length = 0.000193831119 0.00775369872 OK.
All angles in faces OK.
Face flatness (1 = flat, 0 = butterfly) : average = 0.999989587 min = 0.987503483
All face flatness OK.
Cell determinant (wellposedness) : minimum: 0 average: 3.06790921
***Cells with small determinant found, number of cells: 557
<<Writing 557 under-determined cells to set underdeterminedCells
Concave cell check OK.

Failed 1 mesh checks.

There in you can read "Face tets OK".

Can you please check that again for your case.

[geth03]

Originally Posted by Chrisi1984

Hello,

this is a part of the output of checkMesh -allGemetry


There in you can read "Face tets OK".

Can you please check that again for your case.

is there any workaround in case that face tets is not ok?