EFFECT OF VARYING THERMAL CONDUCTIVITY AND VISCOSITY IN UNSTEADY FREE STREAM FLOW OVER STRETCHING SHEET.

The aim of this paper is to investigate two dimensional unsteady flow of a viscous incompressible fluid about stagnation point on stretching sheet in the presence of time dependent free stream velocity. It is assumed that fluid viscosity and thermal diffusivity are assumed to vary as linear function of temperature. Fluid is considered in the presence of radiation effect. Using time-dependent stream function, partial differential equations corresponding to the momentum and energy equations are converted into non-linear differential equations. Numerical solutions of these equations are obtained by using Runge-Kutta Fehlberg method with the help of shooting technique. In the present work the effect of unsteadiness parameter, stretching sheet parameter, temperature-dependent fluid viscosity parameter and thermal diffusivity parameter on flow and heat transfer characteristics are discussed. Skin-friction and Nusselt number at the sheet are computed and discussed. [ABSTRACT FROM AUTHOR]