THE STABILITY OF VERTICAL THERMAL-BOUNDARY-LAYER FLOW IN A POROUS-MEDIUM

We consider the linearised stability characteristics of the thermal bo undary layer induced by the uniform heating of a semi-infinite vertica l surface embedded in a fluid - saturated porous medium. In this paper attention is restricted to two-dimensional disturbances far from the leading edge. This analysis complements and extends the direct numeric al simulation of Rees [1993] which shows that the flow is stable at lo cations sufficiently close to the leading edge. In this asymptotic reg ime we also find that wave disturbances decay. However, the rate of de cay decreases as the distance downstream of the leading edge increases .