Nonsimilar solutions for double diffusive convection near a frustum of a wavy cone in porous media

摘要

A nonsimilar boundary layer analysis is presented for double diffusive convection flow near a vertical frustum of a sinusoidal wavy cone in a porous medium with constant wall temperature and concentration. A coordinate transformation is employed to transform the complex wavy conical surface to a smooth conical surface, and the transformed nonsimilar boundary layer governing equations are then solved by the cubic spline collocation method. Effects of the Lewis number, buoyancy ratio, half cone angle and wavy geometry on the Nusselt and Sherwood numbers for a frustum of a sinusoidal wavy cone in porous media are studied. The harmonic curves for the local Nusselt number and those for local Sherwood number as functions of streamwise coordinate have a frequency twice the frequency of the wavy conical surface. Moreover, an increase in the amplitude–wavelength ratio raises the amplitude of the local Nusselt number and the local Sherwood number. Further, the average Sherwood number and the average Nusselt number for a frustum of a wavy cone are found to be smaller than those for the corresponding smooth frustum cone.