On the depinning of a drop of partially wetting liquid on a rotating cylinder

TL;DR

This paper explores how partially wetting liquid drops on a rotating cylinder undergo a depinning transition as rotation speed increases, revealing a bifurcation similar to that on heterogeneous substrates.

Contribution

It demonstrates the analogy between drops on rotating cylinders and on patterned substrates, identifying a depinning transition via a sniper bifurcation.

Findings

Depinning occurs at a critical rotation speed.

The transition is characterized by a sniper bifurcation.

The behavior parallels that on heterogeneous substrates.

Abstract

We discuss the analogy of the behaviour of films and drops of liquid on a rotating horizontal cylinder on the one hand and substrates with regular one-dimensional wettability patterns on the other hand. Based on the similarity between the respective governing long-wave equations we show that a drop of partially wetting liquid on a rotating cylinder undergoes a depinning transition when the rotation speed is increased. The transition occurs via a sniper bifurcation as in a recently described scenario for drops depinning on heterogeneous substrates.