Electric field effects on the collision efficiency of uncharged water droplets in a linear flow

TL;DR

This study investigates how external electric fields influence the collision efficiency of uncharged water droplets in a linear flow, highlighting the importance of electric, geometric, and non-continuum effects on droplet interactions.

Contribution

It introduces a combined analysis of electric field effects, non-continuum lubrication, and van der Waals forces on droplet collision dynamics in a linear flow.

Findings

Electric field significantly alters droplet trajectories and collision efficiency.

Non-continuum lubrication effects are crucial for accurate collision modeling.

Collision efficiency depends on electric field strength, droplet geometry, and intermolecular forces.

Abstract

We study the dynamics of collisions between a pair of uncharged conducting droplets under the influence of a uniaxial compressional flow and an external electric field. The near-field asymptotic expression for the electric-field-induced attractive force demonstrate that surface-to-surface contact in finite time is facilitated by overcoming lubrication resistance. We demonstrate the significant role of the external electric field on the relative trajectories of two droplets in a compressional flow and provide estimates of the correlation between collision efficiency and the forces induced by the electric field. For droplet collisions in clouds, continuum lubrication approximations become inadequate to capture collision dynamics, and thus we incorporate non-continuum lubrication interactions into our analysis to address this complexity. Our findings reveal the dependence of collision efficiency on the strength of the electric field, geometry of the two interacting droplets, non-continuum effects, and van der Waals forces.