Boundary layer viscoelastic fluid flow over an exponentially stretching sheet

In the present paper, a viscoelastic boundary layer fluid flow over an exponentially stretching continuous sheet has been examined. The flow is assumed to be generated solely by the application of two equal and opposite forces along the x-axis such that stretching of the boundary surface is of exponential order in x. Approximate analytical similarity solutions (zero and first order) of the highly non-linear boundary layer equation are obtained for the dimensionless stream function and velocity distribution function after transforming the boundary layer equation into Riccati type and solving that sequentially. The first-order solution is derived in the form of confluent hypergeometric Whittaker functions. The solutions are verified at the boundary sheet. These solutions (zero and first order) involve an exponential dependence of the similarity variable, the stretching velocity and the stream function on the axial coordinate. The accuracy of the analytical solutions is also verified by the numerical solutions obtained by employing the Runge-Kutta fourth order method with shooting. The effects of various physical parameters on the velocity profile and skin-friction coefficient are also discussed in this paper.