Unsteady Viscous Flow over an Expanding Stretching Cylinder

We study the viscous flow over an expanding stretching cylinder. The solution is exact to the Navier–Stokes equations. The stretching velocity of the cylinder is proportional to the axial distance from the origin and decreases with time. There exists a unique solution for the flow with all the studied values of Reynolds number and the unsteadiness parameter. Reversal flows exist for an expanding stretching cylinder. The velocity decays faster for a larger Reynolds number and a more rapidly expanding cylinder.