ABSTRAKT

This study analyzes the effect of stress relaxation on the mechanism of instability of the thermal convection. It is also worked-out the effect of heat source on the onset of Hadley- Prats flow in a horizontal fluid saturated porous medium with inclined temperature gradients. This investigation is analyzed by using linear stability analysis for a large number of parameter values. The horizontal components of these inclined gradients induce a Hadley circulation, which becomes unstable when vertical components are sufficiently large and this instability is analyzed using three dimensional normal modes. The vertical thermal Rayleigh number is treated as the eigenvalue. The system that constitutes the eigenvalue problem. Which is solved by using Chebyshev tau-QZ method for various modes of thermal instability.