SplitMesh error messages
 

Hi,
I need to split my mesh in order to apply boundary conditions at some internal zero-thickness surfaces.

I used this approach:

1)I exported my mesh (from gambit) applying interior boundary at a zero-thickness surface named "thinsurf".
In this way I get a faceset named thinsurf.

2) modified boundary file by adding two empty boundaries with zero faces, called "thinsurf1" and "thinsurf2".

3) executed "splitMesh . mycase thinsurf thinsurf1 thinsurf2".

I tried using a very 2d simple mesh and it works ok, but using 3d meshes I have a lot of problems.

The output of splitMesh is the following:
[...]
Splitter
{
type attachDetach;
faceZoneName membraneFaces;
masterPatchName thinface1;
slavePatchName thinface2;
triggerTimes 1(0);
manualTrigger off;
active on;
}

Adding topology modifiers
--> FOAM Warning :
From function bool primitiveMesh::checkCellsZipUp(const bool, labelHashSet*) const
in file meshes/primitiveMesh/primitiveMeshCheck.C at line 1471
40 open cells found. Please use the mesh zip-up tool.
Failed 1 mesh topology checks.
Failed some mesh checks.
[...]


And the output of "checkMesh . mycase" gives me a lot of messages like this:


bool primitiveMesh::checkCellsZipUp(const bool, labelHashSet*) const :
Cell 6324 has got 4 unmatched edges:
4
(
(1702 1654)
(1702 551)
(551 192)
(192 1654)
)


--> FOAM Warning :
From function bool primitiveMesh::checkCellsZipUp(const bool, labelHashSet*) const
in file meshes/primitiveMesh/primitiveMeshCheck.C at line 1471
40 open cells found. Please use the mesh zip-up tool.
Writing 40 cells with over used edges to set zipUpCells


I think the problem is in the mesh but if I run checkMesh before using splitMesh everything seems ok. I don't know what to do...

Thank you for any suggestions.

So far I succeeded if my thin
 

So far I succeeded if my thin surface is surrounded by layers of prisms.

Simple tetrahedra cells give errors. Probably the error is due to theaedra having sharp points on the surface...

I had a similar problem with l
 

I had a similar problem with lots of unmatched edges and open cells after splitMesh. I then read the original mesh into Fluent (changed the interior to wall before that) and wrote it out as a case file, and ran fluentMeshToFoam on the case file. The resulting foam mesh is ok.

I also tested a very simple 3D case with internal boundary condition, and that was ok for splitMesh. The original case was about 2 million cells and complicated structure, no tetras, but some prisms. I don't know what exactly is the problem with the larger mesh. If someone is interested in developing splitMesh further, I can test it more or try to find the places and mesh structure where it goes wrong.

Hi,

please just tell me how to run splitMesh and CellSet?
What about the makeCellSets.setSet file.

Thank you in advance!

Boundary conditions (PatchType and vlaue) for newly created boundaries
 

Hello,
I am reviving this old post in hope of understanding the complete picture of how splitMesh works.

I have written my original post here:
https://www.cfd-online.com/Forums/op...wall-mesh.html

My question, in the context of the current thread is: what boundary condtions should I use for the newly generated walls (thinsurf1 and thinsurf2).

1. For example, in 0/p.boundaryField
2. In 0.polyMesh
What should I assinge in places of <?????> ?