CONVECTIVE INSTABILITIES IN ANISOTROPIC POROUS-MEDIA

This paper addresses the problem of the onset of Rayleigh-Benard conve ction in a porous layer using Brinkman's equation and anisotropic perm eability. The critical Rayleigh number and wave number at marginal sta bilities are calculated for both free and rigid boundaries. In both ca ses, it is noted that there exist ranges for which the stability crite ria is intermediate to the low porosity Darcy approximation and to hig h porosity single viscous fluid. The permeability anisotropy is found to select the mode of instability.