Flow Simulations of Axisymmetric Prolate Particles in a Cylindrical Pore

Abstract

The motion of small particles in a fluid is a classical fluid mechanics problem. The present study investigates the motion of axisymmetric prolate spheroids and Cassini ovals of micro-scale through Newtonian and non-Newtonian fluids, bounded by a cylindrical pore. The drag force is numerically obtained over a range of Reynolds number, from creeping flow condition to Re = 40 (for steady state simulations). Both Newtonian and non-Newtonian fluid simulations are carried out, with power-law index values of 0.6, 0.8, 1.0, 1.2, and 1.4, while considering the wall effects due to the cylindrical pore confinement. CFD software package ANSYS CFX is used to model the steady motion of a particle translating in a quiescent fluid along the axis of a coaxial cylinder and to numerically solve the flow around the particle to calculate the coefficient of drag. It is shown that for the different values of power-law index, the drag coefficient increased with increased confinement and decreased with an increase in Reynolds number. The results for bounded creeping Newtonian flow were validated against analytical solutions in the literature. The results are found to be in accordance with the results available in the literature and based on theoretical expectations.