Effects of anisotropy on the transition to absolute instability in a porous medium heated from below

The emerging instability of a forced throughflow in fluid saturated horizontal porous duct rectangular cross section is investigated. heated from below by assuming the boundaries to be at different temperatures. Both and vertical are impermeable basic flow parallel such boundaries. medium anisotropic with permeabilities directions. effect anisotropy on onset buoyancy-driven modal absolute analyzed. parametric conditions leading determined employing an analytical dispersion relation. directions turn out play opposite roles transition instability. It shown that increasing permeability has destabilizing effect, while stabilizing effect.