Three-dimensional flow of a viscous fluid with heat and mass transfer

Three-dimensional unsteady free convection and mass transfer flow of an incompressible, viscous liquid through a porous medium past an infinite vertical flat plate subjected to a time-dependent suction velocity normal to the plate is studied. The equations encountered into the problem are solved using perturbation technique to obtain the velocity, temperature and concentration fields considering ɛ as reference parameter. Expressions for the skin-friction, rate of heat and mass transfers are also obtained. Two cases of most common interest viz. cooling case (Gr > 0) and heating case (Gr < 0) are discussed.