Abstract
This paper describes the incompressible flow of a micropolar fluid through a gap between the concentric uniform tubes. The inner tube being rigid tube and the outer tube has a periodic peristaltic wave travelling down its wall. Mathematical modelling has been carried out for long wavelength approximation. Analytical solutions for the axial velocity and axial pressure gradient have been obtained in closed form. The effects of various emerging parameters on the pressure rise and frictional forces have been discussed. For the present analysis of the endoscope, the correct formula of the friction force per wavelength has been derived. The corresponding results for viscous fluid can be deduced as a limiting case of the present analysis. (C) 2007 Elsevier Ltd. All rights reserved.