Turbulent transport in the mixed convection over a heated horizontal plane

An experimental study is presented of turbulent motions and transport processes over a heated horizontal plane, in which the flow changed from forced convection via mixed convection to natural convection, with heat flux increasing at the plane. In the mixed convection, buoyancy forces were found to enhance the turbulent transport, and the eddy diffusivities of momentum and heat, epsilon sub M and epsilon sub H, and the epsilon sub H/epsilon sub M ratio were found to increase. The stability dependence of this ratio differs significantly for the wall and outer regions: in the wall region this ratio increases slightly with increasing instability, while it changes drastically in the outer layer. Allowance for this fact may be used to predict friction factor, Nusselt number, and profiles of mean velocity and temperature.