In my geometry there are two faces which lies on each other with the same dimension. One extruded normal and other in reverse direction.
The problem is that when I named these faces as upper and lower, it shows an error as overlapping is not allowed in meshing and when I create these faces without merging the faces than I am able to name them. But these are not merge faces so in fluent when I applied interface to these faces, it shows an " error interference zone is not assigned" .
How can I solve this?