Droplets climbing a rotating helical fiber

TL;DR

This study investigates the behavior of liquid droplets on a rotating helical fiber, revealing conditions under which they slide, attach, or climb, supported by experiments and a theoretical model.

Contribution

It introduces a comprehensive experimental and theoretical analysis of droplet dynamics on rotating helical fibers, highlighting the influence of geometry, wetting, and rotation speed.

Findings

Identified the parameter ranges for droplet sliding, attachment, and climbing.

Developed a theoretical model to predict droplet behavior boundaries.

Validated the model with experimental data.

Abstract

A liquid droplet is placed on a rotating helical fiber. We find that the droplet may slide down, attach or climb up the fiber. We inspect experimentally the domain of existence of these three behaviors as a function of the geometrical characteristics of the fiber, its angle relatively to the horizontal, the wetting properties of the fluid and the rotating speed of the helix. A theoretical model is proposed in order to capture the boundaries of the experimental phase diagram.