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-   -   Uncovered faces found ???? (http://www.cfd-online.com/Forums/openfoam-meshing-technical/66048-uncovered-faces-found.html)

hansel July 3, 2009 13:08

Uncovered faces found ????
 
I'm using OpenFOAM-1.5-dev Ubuntu 9.04 64 bit.

I'm attempting to set up a rotating mesh, with a cylinder inside a block with a hole, just a little larger than the cylinder. (the cylinder is about 2M across and the gap is 0.5mm) See picture at end.

When I run it, I get this error:
====================
From function void GGIInterpolation<MasterPatch, SlavePatch>::rescaleWeightingFactors() const
in file /storage/software/OpenFOAM/OpenFOAM-1.5-dev/src/OpenFOAM/lnInclude/GGIInterpolationWeights.C at line 533
Uncovered faces found. On master: 98 on slave: 504
Largest slave weighting factor correction : 0.4458582 average: 0.04798944
Largest master weighting factor correction: 1 average: 0.2857143

Selecting incompressible transport model Newtonian
Selecting RAS turbulence model kEpsilon
kEpsilonCoeffs
{
Cmu 0.09;
C1 1.44;
C2 1.92;
alphaEps 0.76923;
}

Reading field rAU if present


Starting time loop

Courant Number mean: 0.002633346 max: 0.02407465 velocity magnitude: 1.107188
Time = 2.001

Segmentation fault
==============
What is an uncovered face? Does it have to do with the two meshes not lining up perfectly?

I tried it with several different programs:
turbDyMFoam - error and crash
icoDyMFoam - error and crash
IcoFoam error message, doesn't crash, good results.
PotentialFoam error message, no crash, strange results. (velocity changes through ggi interface, like light through a lens.)
traceback on the crash is:
===================
Program received signal SIGSEGV, Segmentation fault.
[Switching to Thread 0x7f7dd8b7d700 (LWP 6293)]
0x00007f7dd8768124 in Foam::mixerGgiFvMesh::calcMovingMasks () from /storage/software/OpenFOAM/OpenFOAM-1.5-dev/lib/linux64GccDPOpt/libdynamicFvMesh.so
Current language: auto; currently asm
(gdb) where
#0 0x00007f7dd8768124 in Foam::mixerGgiFvMesh::calcMovingMasks () from /storage/software/OpenFOAM/OpenFOAM-1.5-dev/lib/linux64GccDPOpt/libdynamicFvMesh.so
#1 0x00007f7dd87690ad in Foam::mixerGgiFvMesh::movingPointsMask () from /storage/software/OpenFOAM/OpenFOAM-1.5-dev/lib/linux64GccDPOpt/libdynamicFvMesh.so
#2 0x00007f7dd87690eb in Foam::mixerGgiFvMesh::update () from /storage/software/OpenFOAM/OpenFOAM-1.5-dev/lib/linux64GccDPOpt/libdynamicFvMesh.so
#3 0x0000000000416047 in main ()
(gdb) list
1 /build/buildd/glibc-2.9/build-tree/amd64-libc/csu/crtn.S: No such file or directory.
in /build/buildd/glibc-2.9/build-tree/amd64-libc/csu/crtn.S
(gdb) Quit
====================

Thanks

http://steve.infiniteeyes.com/mymesh.png

hansel July 3, 2009 13:09

BTW, the GGI questions and answers are spread all over the place. I think there should be an OpenFOAM -> Meshes -> GGI / moving meshes section.

hansel July 3, 2009 23:53

Okay, I made some progress. The uncovered faces are just what it sounds like. When I made my face zones I included the top and bottom. I should have just had the mating faces. So that error is gone.

Unfortunately I'm down to just a core dump with no explanation. It's somewhere in the GGI when it's moving the mesh.

mahaputra July 4, 2009 04:41

Dear Hansel


sorry, just wondering

which meshing generator/tool you use for meshing your posted geometry? (a box with a circle inside)


thanks

hansel July 4, 2009 11:25

Quote:

Originally Posted by mahaputra (Post 221448)
Dear Hansel


sorry, just wondering

which meshing generator/tool you use for meshing your posted geometry? (a box with a circle inside)


thanks

I used blockMesh for the basic cylinder and block. Once I get this working, I plan to carve the test item out of the cylindar using snappyHexMesh.

By the way, if I can ever make this work, I'll write up step by step instructions on how I did it to make it easier for everyone else.

Hasselhoff July 10, 2009 14:05

ggi
 
Hi everybody:)

That's right- it's hard to get ggi- related information. It would be nice if there was some faq somewhere;) GGI worked out real nice for me for nonrotatin and overlapping interfaces- If someone needs information about that, feel free to ask;)
But if I add some nonoverlapping Interfaces, the whole thing doesn't work quite long. I guess the difficulty is how to declare the bridgeOverlap.
The Mesh was generated in Gambit, the Solver is rhoSimpleFoam. The Pictures (interfaces) show the top of a turbomachinery component, walls are periodic.. The flux is supposed to go from the inside through the Honeycomb area.


http://www.bildercache.de/bild/20090710-193333-358.png


http://www.bildercache.de/bild/20090710-193416-833.png



http://www.bildercache.de/bild/20090710-205048-576.png
The honeycomb structures are meshed tri, block (inside) is meshed hex.
My boundary file looks like the following:


HoneyComb_Step
{
type ggi;
nFaces 221;
startFace 1476442;
shadowPatch Step;
zone zone_ HoneyComb_Step;
bridgeOverlap true;
}
Step
{
type ggi;
nFaces 40;
startFace 1476663;
shadowPatch HoneyComb_Step;
zone zone_ Step;
bridgeOverlap true;
}
HoneyComb_Level_2
{
type ggi;
nFaces 2880;
startFace 1476703;
shadowPatch Level_2;
zone HoneyComb_Level_2;
bridgeOverlap true;
}
Level_2
{
type ggi;
nFaces 1289;
startFace 1482568;
shadowPatch HoneyComb_Level_2;
zone zone_Level_2;
bridgeOverlap true;
}
HoneyComb_Level_1
{
type ggi;
nFaces 2985;
startFace 1479583;
shadowPatch Level_1;
zone zone_ HoneyComb_Level_1;
bridgeOverlap true;
}
Level_1
{
type ggi;
nFaces 1064;
startFace 1483857;
shadowPatch HoneyComb_Level_1;
zone zone_Level_1;
bridgeOverlap true;
}
is there a mistake in my boundary- file? Thank you for answering!

best, Mitch


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