dear Sir, I have a problem on the boundary condition: my geometrie is rectangular. I want imposed the following boundary conditions: 1)-Inlet: Vx=Constant; Vy=0 and T=Constant. 2)-Top : Vx=Constant; Vy=0, and dT/dy=0. 3)-Bottom: Vx=Constant; Vy=0, and dT/dy=0. 4)-Outlet: Vx=Constant, Vy=0 and dT/dx=0.

how to make? In particular for the conditions 2,3 and 4. thanks Nabil ALLALOU

You don't need Fluent for this - the solution is a uniform velocity and temperature field: Vx=Constant, Vy=0, T = Constant. OTW, in Fluent, to specify the velocity call the boundaries "velocity inlets", and, with the energy solver enabled, set either specified temperature (your "inlet") or specified flux=0 (your top, bottom, and outlet).