Unsteady mixed convection flow of a viscoelastic fluid near the stagnation point on a vertical surface

Abstract

In this study, unsteady mixed convection in two-dimensional stagnation flow of a viscoelastic fluid around heated surfaces for the case when the temperature of the wall varies linearly with the distance from the stagnation point is investigated theoretically. The governing partial differential equations are transformed into a system of ordinary differential equations, which is then solved numerically by an implicit finite-difference scheme known as the Keller-box method. The numerical solutions obtained are uniformly valid for all dimensionless time from initial unsteady-state flow to final steady-state flow in the whole spatial region. The effects of the viscoelastic parameter K and the mixed convection parameter λ on the flow and heat transfer characteristics are presented in this paper. It is found that there is a smooth transition from the small-time solution to the large-time solution.