Heat conduction through solid rib in periodic duct

Dieter Fauconnier

I have some problems while attempting to simulate the ERCOFTAC case:7.2 (described on the following site (click link)) with Fluent 6.1:

http://tmdb.ws.tn.tudelft.nl/worksho...2/case72d.html

I assumed a periodic geometry where the 2D rib was situated somewhere in the middle of the periodic duct. The smooth wall is adiabatic and a constant heat flux should be defined to the ribbed wall. The ribbed wall consists of three separate parts: a first wall before the rib (adjacent to the fluid), the second wall at the base of the rib itself (adjacent to the solid zone),and a third wall after the rib (adjacent to the fluid). The surface mounted walls of the rib have the coupled boundary condition

When I define a heat flux (e.g. 100W/m2) on the second wall (adjacent to the solid rib zone), the energy-equation (i.e. conduction equation) is not solved in the solid zone, while the convective heat transfer on the other walls (also with a constant heat flux) is solved wel, When I switch boundary conditions to a constant wall temperature (e.g. 500K) on the second wall, the conduction-equation in the solid zone is solved well (and so is the heat transfer on the other walls).

I use a segregated 2nd order implicit unsteady solver and a two-dimensional geometry.

It is important that I can define a heat flux at the base of the rib. Could anyone please help me with this? do I have to use other boundary conditions?

best regards

Dieter