Dynamic simulations of particle suspensions subjected to an external electric field.

摘要

A numerical method is performed to study the suspension of polarizable particles in nonconductive solvents subjected to external electric fields. Such particles experience both hydrodynamic and electrostatic interactions. The hydrodynamic force acting on the particles is determined using the Stokesian dynamics method under the assumption that the Reynolds number is much smaller than 1, while the electrostatic force is determined by differentiating the electrostatic energy of the suspension, which is computed from the induced particle dipoles. In addition, the multiple image method is used to compensate for the electrostatic force when two particles are close to each other. Because the electrostatic energy accounts for both far- and near-field interactions, so does the corresponding force.;In this thesis, a monodisperse suspension of hard, dielectric spheres in a Newtonian fluid contained in a channel and subjected to an electrical field due to energized electrodes embedded in the channel walls was considered. The transient particles motion is studied both under static conditions and when a pressure driven flow is applied, and in the case of a uniform and non-uniform electric field. The results show that the electrostatic energy method applied in the past to the case of a uniform electric field only can be extended to the situation where the electric field is non-uniform.