Convective instability in a horizontal porous layer saturated with oil and a layer of gas underlying it

A theoretical analysis of thermal instability driven by buoyancy forces in transient concentration fields is conducted in an initially quiescent, oil-saturated, horizontal porous layer with gas diffusion from below. Darcy's law is used to explain characteristics of fluid motion and linear stability theory is employed to predict the onset of buoyancy-driven motion. Under the principle of exchange of stabilities, the stability analysis is performed on the basis of the propagation theory which adopts the concentration boundary layer thickness as a characteristic length scaling factor. The prediction compares quite well with existing experimental result. (C) 2003 Elsevier Science Ltd.