[seboxx]

Hi guys,

I have the following problem:
my geometry is very easy, just a plane that I created in gmsh.
The height is only one Layer (extrude... Layers{1}; Recombine.
I am using gmshToFoam and it gets translated. I have tried to use createPatch afterwards but i ve also tried it without. I am defining cyclic boundaries on 4 of the boundaries, that is i connect top to bottom and left to right.

This cyclic boundary conditions seems to make problems here. The solver runs, but i am really unhappy about the result.
I am having a situation with diffusion involved. So the red concentration diffuses into neighbour volumes.
But as you can see in the attached image (the white stuff on the top and bottom and the weird curvature of the red region on the boundaries)
there must be some kind of diffusion in areas that shouldnt be connected at all.

I am using the gmsh approach and not blockMesh because I am planning to model more complex geometries and do a field mapping afterwards.

I am happy about any suggestions

seboxx

[seboxx]

... or here is a more obvious image.

seboxx

[ubbsx]

Hi I know, it is a late reply and you might have found a solution.

you need: createPatch
and a createPatchDict in your system folder.

Then it should work.

[Miguel.Mendez]

Originally Posted by ubbsx

Hi I know, it is a late reply and you might have found a solution.

you need: createPatch
and a createPatchDict in your system folder.

Then it should work.

Hi ubbsx. May you give me more details about this solution?

I am trying something similar. I have a case with cyclic boundary conditions and I have problems when I check my BC in my folder 0/, and the mesh imported from gmsh, both things with ParaFoam. I have changed boundary file in constant/polymesh with the respective syntax of cyclic BC (I used a template from a similar succes case with these BC).

If I use something BC like (inlet/outlet), with no neighbors patch, ParaFoam doesn't crash.

There is a special method for setting up a cyclic case with a mesh imported from gmsh?

Thanks in advance.

Miguel.

[RGS]

Originally Posted by Miguel.Mendez

Hi ubbsx. May you give me more details about this solution?

I am trying something similar. I have a case with cyclic boundary conditions and I have problems when I check my BC in my folder 0/, and the mesh imported from gmsh, both things with ParaFoam. I have changed boundary file in constant/polymesh with the respective syntax of cyclic BC (I used a template from a similar succes case with these BC).

If I use something BC like (inlet/outlet), with no neighbors patch, ParaFoam doesn't crash.

There is a special method for setting up a cyclic case with a mesh imported from gmsh?

Thanks in advance.

Miguel.

I didn't understand what you meant by checking the BC in the 0/ folder and with Parafoam.


But to answer your question, no there is no special method for setting up a cyclic case with a mesh imported from gmsh. Gmsh just gives you a mesh. You still might have to define the patches properly, especially for patches like cyclic that need an entry in the constant/polyMesh/boundary file. createPatch is a utility that helps you to do that. It is an alternative to manually editing the boundary file.

If you can explain a bit more clearly what problem you are facing, I can try to help.

[Miguel.Mendez]

Originally Posted by RGS

I didn't understand what you meant by checking the BC in the 0/ folder and with Parafoam.


But to answer your question, no there is no special method for setting up a cyclic case with a mesh imported from gmsh. Gmsh just gives you a mesh. You still might have to define the patches properly, especially for patches like cyclic that need an entry in the constant/polyMesh/boundary file. createPatch is a utility that helps you to do that. It is an alternative to manually editing the boundary file.

If you can explain a bit more clearly what problem you are facing, I can try to help.

Hi Rohit!!

I really appreciate your answer, your time and interes on helping me. That day, after navigating in other posts, I have found the clue, and with some documetation, I could set up my case.

I hope I would not have more problems and thanks again!