TURBULENT BOUNDARY LAYER HEAT TRANSFER EXPERIMENTS: CONVEX CURVATURE EFFECTS INCLUDING INTRODUCTION AND RECOVERY.

Measurements have been made of the heat transfer rate through turbulent and transitional boundary layers on an isothermal, convexly curved wall and downstream flat plate. The effect of convex curvature on the fully turbulent boundary layer was a reduction of the local Stanton numbers 20 to 50% below those predicted for a flat wall under the same circumstances. The recovery of the heat transfer rates on the downstream flat wall was extremely slow. After 60 cm of recovery length, the Stanton number was still typically 15 to 20% below the flat-wall predicted value. Various effects important in the modeling of curved flows were studied separately. These are: (1) the effect of initial boundary layer thickness, (2) the effect of freestream velocity, (3) the effect of freestream acceleration, (4) the effect of unheated starting length, and (5) the effect of the maturity of the boundary layer. An existing curvature-prediction model was tested against this broad heat transfer data base to determine where it could appropriately be used for heat transfer predictions.