Rotating electroosmotic flow of viscoplastic material between two parallel plates

Abstract

This study aims to investigate electroosmotic flow of a viscoplastic material, modeled as either Bingham plastic or Casson fluid, through a parallel-plate channel that rotates about an axis perpendicular to the plates. A relatively small yield stress, comparable to that of human blood, is considered in order to confine to the condition there is only one yield surface in the flow. An iterative finite-difference numerical scheme is developed to solve the Cauchy momentum equations and nonlinear constitutive equations. The location of the yield surface, and velocity and stress components in both the sheared and unsheared regions are found as functions of the yield stress, rotation speed and Debye parameter. Numerical results are presented to reveal that the system rotation and yield stress may counteract each other in controlling the resultant flow rate and flow direction. The effect of yield stress may even be reversed for a sufficiently large rotation speed.