Peristaltic transport of a non-Newtonian fluid with a peripheral layer

This paper is devoted to the analytical study of the two-dimensional flow o f a power-law fluid with a peripheral layer. The analysis is carried out by using wavelength approximations. The solution has been obtained in the for m of a stream function from which the shape of the interface has been deter mined. The relation between the flow-rate and the pressure difference for o ne wavelength has been derived. This is used to determine the maximum press ure and the maximum flow-rate. The expressions for the efficiency of pumpin g, the trapping limit and the reflux limit have also been determined. The c omputational results indicate that the flow is increased when the value of the flow behaviour index is raised or the viscosity of the outer layer is i ncreased. The study reveals that in the case of physiological flows where t he viscosity of the peripheral layer is usually less than that of the core layer, a thinner peripheral layer is responsible for a greater flow-rate. ( C) 1999 Elsevier Science Ltd. All rights reserved.