• THE UNSTEADY THERMAL CONVECTION IN A MAXWELL FLUID SATURATED POROUS LAYER USING THERMAL NON-EQUILIBRIUM MODEL

Abstract

The stability of a viscoelastic Maxwell fluid saturated horizontal porous layer heated from below and cooled from above when the solid and fluid phases are not in a local thermal equilibrium is examined analytically. The Darcy model is used for the momentum equation and two field model is used for the energy equation each representing the solid and fluid phases separately. The linear stability theory is employed to obtain the condition for the onset of convection. Analytical expression for the occurrence of oscillatory onset is obtained. Linear stability analysis suggests that, there is a competition between the processes of viscous relaxation and thermal diffusion that causes the first convective instability to be oscillatory rather than stationary. Besides, the effect of viscoelastic parameters and the thermal non-equilibrium on the stability of the system is analyzed.