A perturbation analysis of the flow of a Powell-Eyring fluid between coaxial cylinders

The Powell-Eyring generalised viscous fluid model was developed to model the flow of viscous inelastic shear thinning fluids, such as polymer melts and suspensions of solids in non-Newtonian solvents. We consider the helical flow of a Powell-Eyring fluid between infinitely long coaxial cylinders. Such a flow is of relevance to a number of applications, including rheometry. We show that a perturbation approach to the flow problem yields simple explicit expressions for the fluid velocity field, which may then be applied to obtain approximations to other features of the flow.