Meshing a Geometry with Multiple Interfaces
 

Hi all,

I am meshing a simple geometry in ICEM with tetra/prism elements. However, I want to create different fluid zones so that I can define the properties differently in different areas of the volume.

I have attempted to do this by creating interfaces to separate the volume into three zones. Whenever creating two interfaces to separate into three separate zones (bodies), I open the fluent setup and it tells me that I need to define the two interface zones for each specific interface. However, I only have interface_1 and interface_2, and not two zones to match up for each one.

I tried to work around this by creating a duplicate interface at the same exact spot so that I can select the two sides of the interface and match them (which works), but then the mesh is created twice and is overlapped as shown in the picture.

I'm just at a complete loss as to how I'm supposed to handle this issue. The mesh is perfectly fine if I create two interfaces, but I can't assign the interface without two sides to match. When I create two sides to match, the mesh then is created twice and overlaps. Any help with this would be greatly beneficial! Thank you all.

I suppose your initial mesh:
- has three body points in each volume.
- as an effects, has three volumes with a mesh
- and the mesh is conformal over the two interface

Than it sounds like ICEM is ok.
Interfaces in Fluent puzzled me a lot as well (that is one of the reasons I prefer CFX). I noticed that Fluent has difficulties in identifying interfaces automatically. What helped me is to tell Fluent that the volume in the center is a solid, while keeping the outer 2 fluid. Then fluent creates walls on the interfaces.
The second step is to set the solid back to fluid. It will leave the walls, allowing you to turn them into interfaces, and making a proper setup.

Hope this helps, Gert-Jan

Thanks so much for your reply. I've done what you recommended and changed the center volume to solid and then back to fluid, which creates the 'shadows' that are specified as walls.

However, this also changes the interface type to 'wall' as you said, but I then cannot change the type back to 'interface', thus not able to create the two interfaces. When I try to change back to 'interface', the choices are only fan, interior, porous jump, radiator, wall.

Do you have any ideas about this? Thanks again!

Hi,


it's some years ago since i have used fluent. So i am not sure if i remember correctly.


Anyways,...



For structured-only meshes i would create two seperate sub-topologies. Then premesh them individually and merge them when convert them to unstructured. That way two interface meshes would be created. Then fluent would read them as intended. Having just different volume parts wasn't enough.


To do the same with unstructured meshes, i usualyl was meshing and exporting each volume individually. Then i would import those two meshes into fluent where the interfaces would then be created.


I think the main issue is, that ICEM does not expect two surface meshes between different volumes of a mesh. It just creates a single layer interior mesh. Making one SOLID and one FLUID would ICEM tell enough to create a double layered interface mesh, as Gert-Jan told.



Best regards,
Sebastian