Effects of an endoscope and fluid with variable viscosity on peristaltic motion

The influence of an inserted endoscope and fluid with variable viscosity on the peristaltic motion has been investigated under zero Reynolds number. The problem is formulated using a perturbation expansion in terms of a variant wave number. The effects of curvature, viscosity, radius of an endoscope and amplitude of the wave on the pressure rise and friction forces on the inner and outer tubes are analyzed. Peristaltic and augmented pumping are discussed. The results show that, the pressure rise increases with increasing wave number, amplitude ratio and radius ratio. Also, it decreases with increasing viscosity parameter. Further, it is independent of wave number, amplitude ratio, radius ratio and viscosity parameter at certain values of flow rate. A comparison with previous studies is given. © 2003 Elsevier Inc. All rights reserved.