Vibration-induced climbing of drops

TL;DR

This study experimentally demonstrates that liquid drops can climb against gravity on a vibrating inclined surface due to deformation-induced symmetry breaking, enabling controlled drop movement without special surface modifications.

Contribution

It reveals a novel mechanism for drop motion against gravity driven by vibrations and deformation, expanding understanding of fluid dynamics on vibrating surfaces.

Findings

Drops move upward above a vibration threshold

Motion direction correlates with contact angle asymmetry

Vibration frequency influences the drop's movement

Abstract

We report an experimental study of liquid drops moving against gravity, when placed on a vertically vibrating inclined plate, which is partially wetted by the drop. The frequency of vibrations ranges from 30 to 200 Hz, and, above a threshold in vibration acceleration, drops experience an upward motion. We attribute this surprising motion to the deformations of the drop, as a consequence of an up or down symmetry breaking induced by the presence of the substrate. We relate the direction of motion to contact angle measurements. This phenomenon can be used to move a drop along an arbitrary path in a plane, without special surface treatments or localized forcing.