Unsteady heat and mass transfer over a vertical stretching sheet in a parallel free stream with variable wall temperature and concentration

Our aim in this article is to investigate numerically the unsteady two-dimensional mixed convection flow along a vertical semi-infinite stretching sheet in a parallel free stream with a power-law wall temperature and concentration distributions of the form T _w (x) = T _∞ + Ax ^2m-1 and C _w (x) = C _∞ + Bx ^2m-1, where A, B and m are constants. The unsteadiness in the flow is caused by the time dependent stretching sheet as well as by the free stream velocity. The governing nonlinear partial differential equations in the velocity, temperature and concentration fields are written in nondimensional form using suitable transformations. The final set of resulting coupled nonlinear partial differential equations is solved using an implicit finite-difference scheme in combination with a quasi-linearization technique. The effects of various governing parameters on the velocity, temperature and concentration profiles as well as on the skin friction coefficient, local Nusseltnumber and local Sherwood number are presented and discussed in details. The computed numerically results are compared with previously reported work and are found to be in excellent agreement.