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-   -   faceAgglomerate for viewFactor radiation with non-manifold patches (http://www.cfd-online.com/Forums/openfoam-pre-processing/106990-faceagglomerate-viewfactor-radiation-non-manifold-patches.html)

mirx September 14, 2012 05:29

faceAgglomerate for viewFactor radiation with non-manifold patches
 
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Hello,

I am trying to run a simulation with chtMultiRegionSimpleFoam with viewFactor radiation enabled. I create the mesh with snappyHexMesh. This results in non-manifold boundary patches after splitMeshRegions. I have attached a picture to give you an example.

If I try to run faceAgglomerate utility on such a mesh I get the following error:
Code:

--> FOAM FATAL ERROR:
(156 157) not found in table.  Valid entries:
1274
(
(99 100)
...
    From function HashTable<T, Key, Hash>::operator[](const Key&)
    in file /home/opencfd/OpenFOAM/OpenFOAM-2.1.1/src/OpenFOAM/lnInclude/HashTableI.H at line 117.

I have learned that this happens with non-manifold patches only. Unfortunately my geometries are very complex, so that it is not possible to aviod non-manifolds.

I need your help to find a solution to this problem.
Is it in any way possible to run faceAgglomerate, which is based on pairPatchAgglomeration, on a non-manifold surface?
If not, how can I get rid of these non-manifold patches? My only solution would be, to remove the cells of the fluid domain, which are in contact to the non-manifold points, using subsetMesh. But then I get holes in my mesh, which I would like to avoid.
I guess, it is not possible to remove the patch faces around the non-manifold points, as the boundary of the fluid domain would not be completely defined then.
Is it possible to exclude patches from the face agglomeration?

Thank you very much in advance!

Regards

mirx

RobinZ August 5, 2015 03:22

Hello Michael,

i had the same issue. To your question: it is possible to exclude patches from the faceAgglomeration. I did this to avoid this problem. The patches will some kind of ignored while agglomeration, when you dont specify them in the viewFactorsDict. That means, every face is now an agglomerate. So no faces will be agglomerated. But this can lead in an error while viewFactorsGen: "agglomeration does not create a single, non-manifold face for agglomeration". So the problem doesnt have to be fixed with that. Also you can rise the number of agglomerates in your viewFactorsDict to avoid your error. The faceAgglomerate and viewFactorGen utilities are very instable. I hope they will be upgraded soon.

best regards

Robin


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