Effect of Magnetic Field on Thermal Instability of Couple Stress Rivlin Ericksen Ferromagnetic Fluid With Variable Gravity Field Through Porous Medium.

Abstract

The influence of magnetic field on thermal instability of a couple stress Rivlin-Ericksen ferromagnetic fluid layer through porous material in presence of variable gravity field is studied.  The dispersion relation was established and analytically solved using the normal mode method. Couple stress, magnetic field, and medium permeability are found to have both a stabilizing and a destabilizing influence for the stationary convention. Magnetisation always has a stabilizing effect, whether the value of λ is greater than zero or less than zero. It is also possible to see oscillatory modes and stability in the system introduced by the presence of a magnetic field for λ< 0. Oscillatory modes are not permitted in the absence of a magnetic field, and the principle of exchange of stability is satisfied.