Friction and heat transfer for inclined surfaces in relative motion to an air stream under buoyancy effect

Heat transfer from a surface in motion relative to either a stationary or moving fluid occurs in many materials processing applications such as hot rolling, extrusion, drawing, and drying. In this study, an analysis has been carried out to predict the convective transport occurring between air and a continuous inclined surface which moves with an assisting or opposing flow with respect to the free stream in the presence of gravity. The steady flow of air is assumed laminar and is modeled by using a two dimensional (2-D) complete set of conservation equations, subject to the appropriate boundary conditions. The equations were solved numerically by employing the finite element method. Predictions for the local dimensionless skin friction and heat transfer are made for different configurations of the relative position of the surface and the free stream. The numerical results of the present study for the buoyancy-assisting and opposing flows on vertical surfaces are validated by direct comparison with the available published data. New results are presented for inclined surfaces with the buoyancy-assisting and opposing flows. The buoyancy-assisting results are then correlated for wide ranges of inclination angles and moving sheet relative velocities.