Effects of Horizontal Magnetic Field and Rotation on Thermal Instability of a Couple-Stress Fluid through a Porous Medium: a Brinkman Model

A linear stability analysis is carried out to discuss the effects of horizontal magnetic field and horizontal rotation on thermal instability problem of a couple-stress fluid through a Brinkman porous medium. After employing normal mode method on the dimensionless linearized perturbation equations, it is noted that for the stationary state, Taylor number promotes stabilization, whereas medium porosity hastens the onset of convection. The medium permeability , magnetic field , couple-stress and Darcy-Brinkman parameter play dual role in determining the stability/instability of the system under certain restrictions. Also, the sufficient conditions responsible for the non-existence of overstability are gained and the principle of exchange of stabilities holds good for a magneto-rotary system.

Keywords:

Couple , stress fluid , Magnetic field , Rotation , Brinkman porous medium