Peristaltic transport of a non-Newtonian fluid: applications to the vas deferens and small intestine.

The problem of peristaltic transport of a non-Newtonian (Power law) fluid in a uniform and non-uniform tube has been investigated under zero Reynolds number and long wavelength approximation. A comparison of the results with those of Newtonian fluid model shows that the magnitude of pressure rise, under a given set of conditions, is smaller in the case of non-Newtonian fluid, when the flow behavior index n less than 1, at zero flow rate. Further, the pressure rise decreases as n decreases from 1, at zero flow rate, is independent of n at a certain value of flow rate, and increases if flow rate exceeds further. Also, at a given flow rate, an increase in the wavelength leads to a decrease in pressure rise and increase in the influence of non-Newtonian behavior. Pressure rise, in the case of non-uniform geometry, is found much smaller than the corresponding value in the case of uniform geometry. Finally, the analysis has been applied and compared with observed flow rates in the vas deferens in rhesus monkeys and in the small intestine.