[liquidspoon]

Hi all,

I am trying to use mergeMeshes and StitchMesh to attach an inlet port to an annular domain, but am getting stumped on the StitchMesh stage. I would really appreciate assistance on this.

I make the annulus first

blockMesh
mirrorMesh

and everything looks good (figure):
Step 1.jpg

Then I make the port that connects to the side in another case directory (MeshCase), and that comes out fine:

blockMesh

(see figure)
Step 2.jpg

Then I run:

mergeMeshes -overwrite . MeshCase

and both meshes are now combined in the top level mesh. As you can see from the third figure, the grids on both meshes line up perfectly.
Step 3.jpg

Finally, I need to get rid of the dummy patch (inner portion of the inlet port that coincides with the outer boundary of the big mesh). I have tried to use stitchMesh to make this work, but can not figure it out.

Calling:

stitchMesh -partial Wall Dummy

Throws a floating point exception in the projectPoints() stage.

#0  Foam::error::printStack(Foam::Ostream&) at ??:?
#1  Foam::sigFpe::sigHandler(int) at ??:?
#2  ? in "/lib/x86_64-linux-gnu/libc.so.6"
#3  Foam::slidingInterface::projectPoints() const at ??:?
#4  Foam::slidingInterface::changeTopology() const at ??:?
#5  Foam::polyTopoChanger::changeTopology() const at ??:?
#6  Foam::polyTopoChanger::changeMesh(bool, bool, bool, bool) at ??:?
#7  ? at ??:?
#8  __libc_start_main in "/lib/x86_64-linux-gnu/libc.so.6"
#9  ? at ??:?
Floating point exception (core dumped)

If I unset FOAM_SIGFPE, and rerun stitchMesh, I get the specific message:

Bad points:(0.137781 0.980365 0.02) (0.137781 0.980365 0.02) (-0.30265 -1.96664 0.02)

    From function void plane::calcPntAndVec
(
    const point&,
    const point&,
    const point&
)

I'm not really sure what is going on in this stage of the stitchMesh program. I have also tried playing around with toleranceDict, different stich options (perfect, partial, etc.), but no success.

I have attached the case. StitchTest.zip

[wyldckat]

Hi Alex,

The problem is that you have a single patch for the main mesh, leading stitchMesh to get confused about which points from the wall to be used for stitching.

The following did the trick:

blockMesh
mirrorMesh
blockMesh -case MeshCase
autoPatch -overwrite 45
mergeMeshes -overwrite . MeshCase
stitchMesh -overwrite auto1 Dummy

The "-partial" option can't be used in this scenario, because the point correspondence is of type "integral": http://www.openfoam.org/mantisbt/view.php?id=1767#c5338 - see comment #5338

Best regards,
Bruno

[liquidspoon]

Hi Bruno,

Thank you very much for the detailed response and assistance. I am eager to try this out when I get back to the office.

You are a real asset to the community. I owe you a beer if we are ever in the same town for a conference :-).