FREE-CONVECTION FROM A HEATED VERTICAL CYLINDER EMBEDDED IN A FLUID-SATURATED POROUS-MEDIUM

We consider the free convection boundary layer now induced by a heated vertical cylinder which is embedded in a fluid-saturated porous mediu m. The surface of the cylinder is maintained at a temperature whose va lue above the ambient temperature of the surrounding fluid varies as t he n(th) power of the distance from the leading edge. Asymptotic analy ses and numerical calculations are presented for the governing nonsimi lar boundary layer equations and it is shown that, when n < 1, the asy mptotic flowfield far from the leading edge of the cylinder takes on a multiple-layer structure. However, for n > 1, only a simple single la yer is present far downstream, but a multiple layer structure exists c lose to the cylinder leading edge. We have shown that the fully numeri cal and asymptotic calculations are in satisfactory agreement especial ly for exponents n close to zero. Comparisons of the present numerical solutions obtained using the Keller-box method with previous numerica l solutions using local methods are also given.