Unsteady Boundary Layer Flow of Fractional Oldroyd-B Viscoelastic Fluid Past a Moving Plate in a Porous Medium

Abstract

This paper considers the unsteady boundary layer flow over a moving flat plate embedded in a porous medium with fractional Oldroyd-B viscoelastic fluid. The governing equations with mixed time-space fractional derivatives are solved numerically by using the finite difference method combined with an L1-algorithm. The effect of various physical parameters on the velocity and average skin friction are discussed and graphically illustrated in detail. Results show that the porosity $ϵ$ and fractional derivative $α$ enhance the flow of Oldroyd-B viscoelastic fluid within porous medium, but fractional derivative $β$ weakens the flow. Moreover, it is found that the average skin friction coefficient rises with the increase of fractional derivative $β.$