Dynamic Simulation of Electro-Hydrodynamically Interacting and Sedimenting Particles

TL;DR

This study models the complex interactions of sedimenting dielectric particles under electric fields, revealing how external fields and particle arrangements influence sedimentation dynamics and the surrounding fluid flow.

Contribution

It introduces a combined simulation approach using Stokesian Dynamics and grand Capacitance matrix to analyze electro-hydrodynamic interactions in sedimenting particles with external electric fields.

Findings

Electric fields significantly alter particle sedimentation behavior.

Particle arrangements affect the net drag force experienced.

Sedimentation induces a background velocity field in the medium.

Abstract

Particle-particle interactions in sedimenting systems have been investigated in the present study considering the many-body hydrodynamic and electrodynamic interactions. These interactions primarily occur in two modes: near-field and far-field interactions. The hydrodynamic interactions are modeled employing the Stokesian Dynamics while the electrodynamic interactions are accounted using the grand Capacitance matrix formulation capable of tackling externally applied arbitrary electric field effects. It is seen that the presence of an external electric field and asymmetry in particle positioning greatly modifies the dynamics of the rigid dielectric spherical particles when compared with the sedimenting system without the electric field effects. This is attributed to the induced dipole moment interactions among the particles. A consequence of the alterations in the particle arrangements also changes the net drag force experienced by these sedimenting particles, which is also reported in the present study. Furthermore, we have evaluated the induced background velocity field of the continuous medium due to sedimentation of the particles. A net velocity is observed in the continuous medium due to the sedimentation-induced particle rotation, which is found to vary in presence of an external electric field.