Boundary condition problem
 

Hello Friends,

I am trying to simulate the solar chimney problem with vertical axis turbine. I created the mesh in ICEM. I put a simple curve to define a turbine. But in Fluent, how can I give the pressure difference across the turbine. What boundary condition should I use? I have tried using two interfaces but didn't work.
(Schematic is in the attachments)

Also, every time I am getting divergence in Temperature. I have given convection boundary condition to collector and heat flux to the ground.

Any idea what could be the problem?

Thanks in advance.