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-   -   Fluent Interface BC (https://www.cfd-online.com/Forums/fluent/108799-fluent-interface-bc.html)

eishinsnsayshin November 1, 2012 15:57

Fluent Interface BC
 
Hello All,

I am using ANSA 13.2.3 to import my surface/volume mesh into FLUENT 14.0. I have prism layers on some walls. ANSA automatically created "side quad Default pshell property"s on the sides of exposed prism layers. When I import the .msh file into FLUENT, these side quad shells are automatically made into "interface" boundary conditions.

This is strange to me because in the past, every other mesh that I've imported into FLUENT that involved prisms created a wall BC for the side quad shells for both it and its "shadow surface".

Anyone out there have any idea why FLUENT would create an interface BC for a surface instead of creating a shadow surface to later be changed from a wall to interior?

What exactly is the difference between interior zones and interface zones?

Thanks!
I'm having a hard to time finding info on interface zones.

vangelis November 6, 2012 08:52

Hi there,

I assume you have generated layers in ANSA using the option
in LAYERS window
Tab Side treatment
Generate Quad-Tria interface ON

This means that at the boundaries of the PIDs from which you grow
layers ANSA generates TWO PIDs.
Side Quad AND
Side Tria

and sets them as type interface.

When you read them in Fluent you need to define
them as one interface from DEFINE>Mesh Interfaces
You select these two PIDs and Fluent will "merge" them as
a non conformal interface.

So interface in Fluent is merging of two different type meshes
while
Interior is a single transparent to the flow boundary.

hope this helps

Vangelis

eishinsnsayshin November 8, 2012 11:54

Thanks for the reply,

Yeah, in the past I have always just deleted all the side tria interface default shells that are created during the layer creation. That way, when I run a penetration intersection check, ANSA will not detect the intersection of a side tria with a side quad. It's always worked out fine.

What I ended up doing was regenerating the layers and hexa int. mesh and it worked okay the second time. Weird, but I think I know what happened, or at least I solved my own problem (I'll post what happed for future posters that might have this weird problem):

What I truly have is a large hexa interior volume with a few mapped meshes within that large domain. If I do an volumes>auto detect, it will detect the large volume, as well as the smaller volumes to be map meshed. What I was doing before was creating prisms, meshing the large domain, then the smaller mapped meshes inside my domain. The problem with mapped mesh though is that the volume cannot be defined already. So I would have to go to my volume list, do a "show only" of my smaller mesh for mapped meshing, then delete the auto-detected volume associated with my mapped mesh area so it would let me do a map mesh. After creating the mapped mesh however, the previously created domain hexa-int. volume mesh would be automatically delected, probably because my mapped mesh touched the domain volume mesh? I don't know, it shouldn't matter but that's what it was doing. Anyways, I would then have to again create my hexa int domain volume mesh. When I did this, fluent made that interface boundary, even though there were only side quads, no side trias. This is probably because I had to recreate hexa int. mesh for my domain, after it was automatically deleted once already, making it think that the layers didn't match up with the hexa int mesh (maybe?).

I've learned the correct way for me to do this is create the prisms, auto detect all volumes, map mesh my mapped mesh areas (will still need to delete each auto detected volume prior to map meshing), then mesh the hexa int volume mesh last. This worked for me.

Thanks again for your reply though! I now understand the interface better!

vangelis November 9, 2012 03:09

glad about it!


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