MHD boundary layer flow due to an exponentially shrinking sheet

This investigation deals with the MHD boundary layer flow due to an exponentially shrinking sheet. The sheet is assumed to be porous and a variable wall mass transfer is considered. The governing equations of motion are transformed into a nonlinear selfsimilar ordinary differential equation. Then the converted equation is solved numerically using the shooting method. The numerical computations yield that the requirement of wall mass suction for the steady flow is reduced when the magnetic field is imposed, i.e. the magnetic field itself delays the boundary layer separation and preserves the steady flow. In addition, dual solutions for the steady MHD flow are found for certain conditions. With the increasing magnetic parameter, the velocity increases for the first solution and decreases for the second solution. 1. Introduction. The viscous incompressible flow of Newtonian fluid due to a linearly stretching sheet was first investigated by Crane [1], who obtained an exact similarity solution. The work of Crane [1] was extended by many researchers. In this regard, Magyari and Keller [2] introduced a new type of the stretching sheet problem by considering the flow due to a sheet stretched exponentially in its own plane, and they investigated also the heat transfer characteristics for the flow taking the exponentially varying wall temperature. Elbashbeshy [3] also discussed the flow and heat transfer over an exponentially stretching surface in the presence of wall mass suction. Partha et al. [4] reported a similarity solution for mixed convective flow due to an exponentially stretching surface by taking into consideration the influence of viscous dissipation on convective transport. Later, Khan and