Boundary conditions on internal faces
 

Hello

I have been looking in the past couple of days for a way to define a wall BC on internal faces. It seems to be a recurrent question, however the few threads about this subject didn't help me. I'm quite new with OpenFoam so that may be the reason.

If I'm right, here are the following steps I need to follow and my questions about each step
- create my mesh using blockMesh (should I define my internal faces into a patch category? it seems to create errors to do so?)

- using faceSet (not sure which function of faceSetDict I should use but I tried with boxToFace, and it creates a folder Sets with two files inside interface_wall and interface_wall_old -> why two? I have "backing up interface_wall into interface_wall_old")

Until now it seems ok: the file interface_wall seems to actually have something inside, but the interface_wall_old file has nothing inside:
0
(
)
I'm wondering why?

And then I change my boundary file, by increasing my number of face by 1 and adding this boundary
interface_wall1
{
type wall;
nFaces 0;
startFace =nFaces+startFace of previous boundary;
}

and then when I call createBaffles interface_wall interface_wall1, I get the fatal error:
Cannot find faceZone interface_wall
Valid zones are
0
(
)

I'm not sure about the difference about sets/zones...?


Can someone help me? I hope the description of my problem is clear enough
I'm using OpenFoam 1.7.0

Thanks for your help
Caroline