The heat and mass transfer of a steady three dimensional natural convection flow of a viscous incompressible fluid between two vertical walls filled with porous materials with heat and mass transfer is investigated. The temperature and concentration of a plate is assumed to have periodic. The governing equations in non-dimensional form are solved by using the perturbation technique. Approximate solutions are derived for Velocity, Temperature and Concentration field. The effect of various non dimensional parameters on Velocity field, Temperature field, Concentration field are discussed graphically.

Keywords : Free Convection, Heat and Mass transfer, Porous Medium, perturbation technique, Periodic temperature and concentration.