On the Characterization of Nonoscillatory Motions in Maxwell Fluid in a Porous Medium Heated from Below

In the present paper condition for characterizing nonoscillatory motions which may be neutral or unstable in a horizontal layer of Maxwell fluid in a porous medium (modified Darcy-Brinkman-Maxwell Model) heated from below is obtained. It is proved that for a horizontal layer of Maxwell fluid in a porous medium heated from below an arbitrary neutral or unstable mode of the system is definitely nonoscillatory in character and in particular the ‘ principle of the exchange of stabilities’ is valid if (RλP_r)/4∏ ∧ 2≤ 1. The result is uniformly valid for all combinations of free and rigid boundaries.