A hierarchical levitating cluster containing transforming small aggregates of water droplets

TL;DR

This paper introduces a novel hierarchical levitating droplet cluster composed of transforming water droplet aggregates, combining electrostatic and aerodynamic forces, with dynamic restructuring and stable outer layers.

Contribution

It presents the first description of a hierarchical levitating droplet cluster with a unique organization and dynamic restructuring, differing from previous simple structures.

Findings

Clusters have hierarchical organization with small aggregates and larger structures.

Droplet aggregates continuously restructure due to electrostatic and aerodynamic interactions.

Outer layers of the cluster form stable hexagonal structures.

Abstract

A new type of a levitating droplet clusters composed of often transforming small aggregates of water droplets is described for the first time. Unlike earlier observed droplet clusters controlled by aerodynamic forces, which formed either an ordered hexagonal structure or a chain structure, the cluster under consideration has a hierarchical organization. Small groups of closely spaced or packed droplets with interactions controlled by the electrostatic force are combined into larger structures controlled by aerodynamic forces. Since charged droplets in the nucleus of the cluster do not have dynamically stable configurations, droplet aggregates keep continuously restructuring. However, droplets with lower charge in external layers of the cluster form a stable hexagonal structure.