Hello Rob,nThe mesh is connected when I see through the sectional plane. As you said there are some wall and wall shadows. But this comes to the case when I want to specify different BC for them.nActually, I found the problem. I don't know if this is common. When there is a surrounding area around the 3 geometries. Then, there is an interior being created between the geometries by the fluent tool automatically. This interior is acting as a barrier and not letting to pass the heat and I cannot change it to the wall because it is in the fluid zone.nWhen there is no surrounding area, there is heat distribution between the geometries.nThe pictures show you the geometry and interiors(if present). The first two picture shows geometry with surrounding domain and interior being created. The last two pictures show no surrounding area and no interior. n nn