Keywords: Mixed convection, Richardson number, lid-driven cavity, temperature gradients.

Abstract: In this study, the mixed convective heat transfer in a lid driven cubic cavity at is investigated numerically. Two cases are negotiated, the top moving lid and the bottom walls are at constant uniform temperatures (case 1: Ttop > Tb, case 2: Ttop < Tb) while the vertical walls are thermally insulated. The Reynolds number is fixed at Re=100, while the Richardson number is varied from 0.001 to 10. The effect of temperature gradient orientation on the fluid flow and heat transfer has been performed. It is shown that the downward temperature gradient yields a better heat transfer rate than the upward temperature gradients (case 1). Multiple correlations in terms of the heat transfer rate and Richardson number has been established.