Natural convection flow from a vertical permeable flat plate with variablesurface temperature and species concentration

Concerns the laminar flows front a permeable heated surface which arise in fluids due to the interaction of the force of gravity and density differenc es caused by the simultaneous diffusion of thermal energy and of chemical s pecies, Species concentration levels in air are assumed to be small in many processes in the atmosphere. Under the usual Boussinesque approximations, a set of non-similar equations for combined buoyancy effects and the permea bility of the surface are obtained The resulting equations have been integr ated by four distinct methods: perturbation method for small transpiration rate, asymptotic solutions for large transpiration rate; Keller-box methods ; and local non-similarity method for any transpiration rate. Effects of va rious practical values of the Schmidt number of the multiple buoyancy param eter and that of the transpiration rate of fluid through the surface on the local skin-friction, the local Nusselt number and the local Sherwood numbe r are shown graphically as well as in tabular form.