FREE STREAM TURBULENCE EFFECTS ON HEAT-TRANSFER FROM A CIRCULAR-CYLINDER WITH UNIFORM SURFACE HEAT-FLUX

Many modern turbine blade sections, even at the high Reynolds numbers at which they operate, manifest considerable areas over which the boundary layer remains laminar in a steady, low-turbulence stream. It is known that free stream turbulence augments the rate of heat transfer in flows with large streamwise pressure gradients. In this paper, we have formulated an expression for the eddy diffusivity induced by the free stream turbulence intensity and integral length scale. The eddy diffusivity model was applied to a cylinder situated in uniform crossflow with superimposed free stream turbulence. The boundary condition of uniform surface heat flux for the cylinder has been considered. A numerical solution of the governing momentum and energy equations with the proposed eddy diffusivity model yielded satisfactory predictions for the Nusselt number and skin friction coefficient. These predictions are compared with the experimental data and the agreement between the two is found to be satisfactory.