CFD Online Discussion Forums

CFD Online Discussion Forums (
-   STAR-CCM+ (
-   -   Complex Interface Mesh (

Jonny6001 February 12, 2011 07:05

Complex Interface Mesh

I have a case which has a fairly complex interface between solid-fluid and solid-gas.

I have a nice surface mesh on all parts. I then create the contact in-place interface between the relevant faces. I then re-run the surface re-mesher because the interface need to be conformal. I then run my volume mesh.

The overall quality of the mesh is good but on some of the interface faces, I have small patches with what looks like holes. They are not holes in the actual surface because the leak detector doesn't find any leaks plus the volume mesher wouldn't run if they were holes.

I am sure that they are not treated as holes. My feeling is they are cells that could have been outside the interface tolerance and therefore are not treated as being part of the interface.

Have you guys come accross this issue? Could it be solved by refining the surface meshes?
I have attached a close-up of an example in the link below.

Thanks a lot for your time.

xamo February 14, 2011 03:27

Hello Jonny6001,

check the mesh at the interface after running the surface remesher. I made the experience, that the remesher sometimes builds two different meshes on the contact interface.

If your interface 2d mesh is ok, you do not need to run the surface remesher after creating the in-place interface. Just build the volume mesh and everything should be ok.


and_ February 15, 2011 10:27

Are you showing just the interface or also the corresponding wall in the picture?
This looks like the interface was not created in all areas. Some cells are still part of the wall.
It is advisable to use the mult-region imprint tool, that is part of the surface repair tool, before remeshing.
This tool converts to seperate boundaries, that are part of different regions into one interface. That way mismatch between interface boundaries during the meshing process is avoided.
In that tool you can specify a tolerance and automatically browse through contacting boundary faces

Jonny6001 February 16, 2011 05:59

Thanks a lot for your help.
I have sorted it out. The surfaces are very high quality so I didn't have to perform any repair. I changed some of the surface mesh in the regions where there was tight curvature and both sides of the interface slowly converge.
I guess if you can afford to use exactly the same mesh specs on both regions, the interface would naturally be close.

It was exactly as you described, some of the faces outside the interface tolerance were left in the original wall.

The multi-region imprint and surface repair toolbox is something I will certainly be interested in learning. I usually spend all my time using Catia to prep the surfaces perfectly, re-import in to Catia as an IGES then re-check the surfaces after the IGES conversion.
I have extensively used the surface wrapper but would prefer if I didn't have to.

Again, thanks a lot to both of you.

All times are GMT -4. The time now is 16:54.