double diffusion from a horizontal cylinder of elliptic cross section with uniform wall heat and mass fluxes in a porous medium

this work studies the double diffusion near a horizontal cylinder of elliptic cross section with uniform wall heat and mass fluxes in a fluid-saturated porous medium. a coordinate transformation is used to obtain the non-similar governing boundary layer equations. the transformed equations are solved numerically by an efficient cubic spline collocation method. results for the local surface temperature and the local surface concentration are presented as functions of the lewis number, the buoyancy ratio, and the aspect ratio when the major axis of the elliptical cylinder is vertical (slender orientation) and horizontal (blunt orientation). as the lewis number is increased, the local surface concentration decreases while the local surface temperature increases. moreover, an increase in the buoyancy ratio tends to decrease both the local surface temperature and the local surface concentration.