Journal of Applied Mathematics
Volume 2012 (2012), Article ID 634806, 15 pages
Research Article

Soret and Dufour Effects on Natural Convection Flow Past a Vertical Surface in a Porous Medium with Variable Viscosity

1Department of Mathematics, Institute of Road and Transport Technology, Erode, Tamilnadu 638316, India
2Department of Mathematics, K. S. Rangasamy College of Technology, Tiruchengode, Tamilnadu 637215, India

Received 25 July 2011; Accepted 1 November 2011

Academic Editor: Elsayed M. E. Zayed

Copyright © 2012 M. B. K. Moorthy and K. Senthilvadivu. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


The heat and mass transfer characteristics of natural convection about a vertical surface embedded in a saturated porous medium subject to variable viscosity are numerically analyzed, by taking into account the diffusion-thermo (Dufour) and thermal-diffusion (Soret) effects. The governing equations of continuity, momentum, energy, and concentrations are transformed into nonlinear ordinary differential equations, using similarity transformations, and then solved by using Runge-Kutta-Gill method along with shooting technique. The parameters of the problem are variable viscosity, buoyancy ratio, Lewis number, Prandtl number, Dufour effect, Soret effect, and Schmidt number. The velocity, temperature, and concentration distributions are presented graphically. The Nusselt number and Sherwood number are also derived and discussed numerically.