ANISOTROPIC THERMOCONVECTIVE EFFECTS ON THE ONSET OF DOUBLE-DIFFUSIVE CONVECTION IN A POROUS-MEDIUM

The linear stability of the thermodiffusive equilibrium of a binary mixture of two miscible fluids in a horizontal plane porous layer is investigated. The linear theory is based on the normal mode analysis under the small amplitude assumption. The effect of anisotropic thermo-convective currents on the stability is obtained. The effect of Prandtl number, ratio of diffusivities and separation parameter are presented graphically. It is found that the thermo-convective currents have a stabilizing effect as well as a destabilizing effect with respect to the case in which these currents are absent. We also find that either a stationary instability or oscillatory instability can occur as the first bifurcation. Some of the results about the former problems are deduced.