Sliding, vibrating and swinging droplets on an oscillating fibre

Abstract

We study experimentally the dynamics of a water droplet on a tilted and vertically oscillating rigid fibre. As we vary the frequency and amplitude of the oscillations the droplet transitions between different modes: harmonic pumping, subharmonic pumping, a combination of rocking and pumping modes, and a combination of pumping and swinging modes. We characterise these responses and report how they affect the droplet's sliding speed along the fibre. The droplet swinging mode is explained by a minimal model making an analogy between the droplet and a forced elastic pendulum.