Axisymmetric creeping motion of particles towards a circular orifice or disk

Abstract

Wall effect on the hydrodynamic interaction among particles is important for their transport in many applications such as filtration. We investigate an axisymmetric creeping flow caused by one or two spherical particles migrating towards a circular orifice or disk. A boundary integral/element method is used to solve for the flow field and calculate the drag force. A crucial advantage of this approach is its capability of tackling a problem with more than one particle in the close vicinity of a solid wall. In the absence of a second particle, our results for the particle drag force agree more favorably with asymptotic behaviors than those from a superposition/collocation method. For cases with two particles driven by a constant external force, a relative motion between them arises from the hydrodynamic friction of the solid wall, leading to a decrease in the evolved separation distance or even occurrence of coagulation. © 2013 AIP Publishing LLC.