Separated Flow Through a Gap Between Two Coaxial Peristaltic Tubes

A peristaltic endoscope is a device that could locomote through curving and tortuous spaces where it has many real-life applications in different disciplines e.g., in the field of medicine, it helps in the process of catheterization in curved tubes which in turn relieve patient's pain. The aim of this paper is to study a trapping phenomenon at the centerline of a gap between inner peristaltic endoscope and outer peristaltic tube of a fluid with viscosity variation and a novel phenomenon of separated flow at the boundary of these tubes. For understanding these phenomena, we formulate the flow of a fluid with viscosity variation through the gap between two coaxial peristaltic tubes in cylindrical coordinates with neglecting Reynolds number and wave number. Explicit forms for the velocity field, pressure rise and friction forces on inner and outer peristaltic tubes in terms of radius ratio, flow rate, parameter of viscosity and occlusion have been obtained. A new comparison between a rigid endoscope and a peristaltic endoscope through the gastrointestinal tract has been made for the pressure rising and drag (friction) forces results. Also, we identify type of pumping for various physical parameters of interest. In addition, separated flow points are determined numerically by using computer algebra system.