I am simulating the Rayleigh-Benard convection in a square enclosure filled with water using the fluent. The boundary conditions are such as, constant heat flux at bottom plate and constant temperature at top plate, side walls are adiabatic. What should be the value of Rayleigh number for the turbulent flow in natural convection heat transfer in a square enclosure filled with water?Which viscous model should I used, laminar or turbulent models?