Effect of variable gravitational field on thermal instability of a rotating fluid layer with magnetic field in porous medium

摘要

The effect of variable gravitational field on thermal instability of a rotating fluid layer in the presence of magnetic field in porous medium is investigated. It is found that the system is stable when gravity is decreasing upwards. The principle of exchange of stability is valid in the absence of rotation and magnetic field when gravity increases upwards. In the stationary convection, rotation has stabilizing or destabilizing effect depending Upon whether gravity is increasing or decreasing upwards.