Turbulent Mixed Convection Along a Vertical Plate

Abstract

Information on heat transfer characteristic of mixed convection in fully developed turbulent boundary layer flow is currently lacking in the literature. Oosthuizen employed a mixing-length model, in which the buoyancy effect was included in the turbulent diffusivities, to analyze turbulent mixed convection flow along an isothermal vertical flat plate under low free-stream velocities and Grashof numbers in the range of 10{sup 8.5} to 10{sup 9.5} (i.e., in the free convection dominated regime). He adjusted the empirical constant in his proposed model and obtained a fair agreement between the experimental data of Hall and Price and his predicted values. Both studies, however, were limited to a small range of the turbulent mixed convection regime close to the pure turbulent free convection limit. Turbulent mixed convection along a vertical flate plate in cross flow has been studied analytically by using the mixing-length model and experimentally. In the present Note, mixed convection in turbulent boundary layer flow along an isothermal vertical flat plate is analyzed for the entire mixed convection regime, ranging from pure forced convection to pure free convection, by employing a modified Van Driest mixing-length model for the turbulent diffusivities that account for the buoyancy effect. This approach is a simplemore » attempt to treat the turbulent mixed convection problem, but it does provide good numerical results, particularly for the forced convection dominated regime.« less