Lattice Boltzmann simulation of a single charged particle in a Newtonian fluid.

Abstract

The lattice Boltzmann method is used to study the sedimentaion of a single charged circular cylinder in a two-dimensional channel in a Newtonian fluid. When the dielectric constant of the liquid is smaller than that of the walls, there are attractive forces between the particle and the walls. The hydrodynamic force pushes the particle towards the centerline at low Reynolds numbers. Due to the competition between the Coulomb force and the hydrodynamic force in opposite directions, there is a critical linear charge density q(c) at which the particle will fall vertically off centerline, which is a metastable state in addition to the stable state on centerline, for any initial position of the particle sufficiently far from the proximal wall. It is found that the rotation of the particle plays an important role in the stability of such metastable states. The particle hits on the wall or falls on the centerline when the linear charge density on the particle is greater or less than q(c). The simulation method and the new phenomena are also helpful in the study of charged multiparticle suspensions.