EFFECT OF NONUNIFORM BOUNDARY TEMPERATURES ON THERMAL-INSTABILITY IN A POROUS-MEDIUM WITH INTERNAL HEAT-SOURCE

The effect of horizontal temperature gradients due to non-uniform heating of the boundaries on the onset of convection in a fluid saturating a porous medium with uniformly distributed internal heat sources is studied using Galerkin method. The results reveal that (i) convection sets in via stationary longitudinal modes, (ii) the presence of internal heat sources promotes the onset of convection. its effect being more at higher horizontal gradients, (iii) stationary transverse modes are not possible in a system with internal heat sources, (iv) transverse oscillatory modes are possible only for small magnitudes of the internal heat source parameter eta, (v) the critical Rayleigh number increases with horizontal gradients.