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Abstract

In this paper, we consider the unsteady hydrodynamic flow of an incompressible Oldroyd-B fluid in a parallel plate channel, initially induced by a constant pressure gradient. The pressure gradient is suddenly withdrawn and the upper plate moves with a uniform velocity while the lower plate continues to be at rest. The arising flow is referred to as run up flow. The unsteady governing equations are solved as initial value problem using Laplace transform technique. The expressions for velocity, shear stresses on both plates and discharge are obtained. The behaviour of the velocity, shear stresses and mass flux has been discussed in detail with respect to variations in different governing flow parameters and is presented through graphs.