Symmetry-breaking in drop bouncing on curved surfaces

TL;DR

This study reveals that drops bouncing on curved Echevaria leaves exhibit asymmetric dynamics due to leaf architecture, leading to a significant reduction in contact time, with potential implications for fluid dynamics and surface design.

Contribution

The paper demonstrates for the first time that curved, cylindrical leaf surfaces induce asymmetric drop bouncing, reducing contact time by approximately 40%.

Findings

Asymmetric bouncing observed on curved surfaces.

Reduced contact time by ~40%.

Asymmetry caused by surface architecture affecting fluid dynamics.

Abstract

The impact of liquid drops on solid surfaces is ubiquitous in nature, and of practical importance in many industrial processes. A drop hitting a flat surface retains a circular symmetry throughout the impact process. Here we show that a drop impinging on Echevaria leaves exhibits asymmetric bouncing dynamics with distinct spreading and retraction along two perpendicular directions. This is a direct consequence of the cylindrical leaves which have a convex/concave architecture of size comparable to the drop. Systematic experimental investigations on mimetic surfaces and lattice Boltzmann simulations reveal that this novel phenomenon results from an asymmetric momentum and mass distribution that allows for preferential fluid pumping around the drop rim. The asymmetry of the bouncing leads to ~40% reduction in contact time.