Internal Patches : Which boundary conditions?

Gearb0x · April 20, 2010, 04:56

Dear all,

I have suceeded in incoportaring a fluent mesh with internal patches.

Now I have to choose the boudary conditions I want at this patches but I can't figure out which one to choose.
Zerogradient is not the good solution.

Has anyone ever had such situation and if so what did you do?

Thanks for your help!

Hydro1004 · April 20, 2010, 20:45

Hi,

I've just come across this problem also.

If anyone knows of a boundary condition that causes OpenFoam to ignore the boundary (so it has no effect on the fluid flow) it would be great to hear!

Cheers,
Marion

herbert · April 21, 2010, 10:51

Hi,

what do you mean with "internal patches"? Is it something like a pair "wall" - "wall-shadow"?
If so you can use the stitchMesh utility to make these faces internal.

Regards,
Stefan

Gearb0x · April 21, 2010, 11:33

A very stupid sketch but it explains the situation very cleary

http://img714.imageshack.us/img714/21/sketchl.png

herbert · April 21, 2010, 14:26

Hi,

I think I understand your problem. The boundary faces should be present twice on two different patches (otherwise they would have owners and neighbours and would therefore be internal). Find the co-located patches (e.g. by checking with paraView) and use
stitchMesh <internalPatch> <colocatedInternalPatch>
for both internal boundaries to make all the faces internal. The entry in the boundary-file should show nFaces=0 after this.

Tell me if it works
Stefan

April 20, 2010, 04:56	Internal Patches : Which boundary conditions?	#1
Gearb0x Senior Member Join Date: Nov 2009 Posts: 111 Rep Power: 16	Dear all, I have suceeded in incoportaring a fluent mesh with internal patches. Now I have to choose the boudary conditions I want at this patches but I can't figure out which one to choose. Zerogradient is not the good solution. Has anyone ever had such situation and if so what did you do? Thanks for your help!

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April 20, 2010, 20:45		#2
Hydro1004 New Member Dan, Mai-Chi and Marion Join Date: Mar 2010 Posts: 9 Rep Power: 16	Hi, I've just come across this problem also. If anyone knows of a boundary condition that causes OpenFoam to ignore the boundary (so it has no effect on the fluid flow) it would be great to hear! Cheers, Marion

April 21, 2010, 10:51		#3
herbert Senior Member Stefan Herbert Join Date: Dec 2009 Location: Darmstadt, Germany Posts: 129 Rep Power: 17	Hi, what do you mean with "internal patches"? Is it something like a pair "wall" - "wall-shadow"? If so you can use the stitchMesh utility to make these faces internal. Regards, Stefan

April 21, 2010, 11:33		#4
Gearb0x Senior Member Join Date: Nov 2009 Posts: 111 Rep Power: 16	A very stupid sketch but it explains the situation very cleary http://img714.imageshack.us/img714/21/sketchl.png

April 21, 2010, 14:26		#5
herbert Senior Member Stefan Herbert Join Date: Dec 2009 Location: Darmstadt, Germany Posts: 129 Rep Power: 17	Hi, I think I understand your problem. The boundary faces should be present twice on two different patches (otherwise they would have owners and neighbours and would therefore be internal). Find the co-located patches (e.g. by checking with paraView) and use stitchMesh <internalPatch> <colocatedInternalPatch> for both internal boundaries to make all the faces internal. The entry in the boundary-file should show nFaces=0 after this. Tell me if it works Stefan