Modelling the Dynamics of Partially Wetting Droplets on Fibres

TL;DR

This study uses lattice Boltzmann simulations to explore how partially wetting droplets behave on fibres, revealing regimes of steady motion, breakup, and oscillation depending on physical parameters.

Contribution

It introduces a detailed simulation analysis of droplet dynamics on fibres, identifying three distinct regimes and their dependence on Bond number and fibre radius.

Findings

Steady-state velocity scales linearly with body force.

Satellite droplet formation increases with fibre curvature.

Droplet shape oscillates periodically in certain regimes.

Abstract

We simulate gravity driven dynamics of partially wetting droplets moving along a fibre using the lattice Boltzmann method. For the so-called clamshell morphology, we find three possible dynamic regimes upon varying the droplet Bond number and the fibre radius: compact droplet, droplet breakup and droplet oscillation. For small Bond numbers, in the compact droplet regime, the droplet reaches a steady state and its velocity scales linearly with the driving body force. A similar scaling law can also be observed for the barrel morphology. For higher Bond numbers, in the droplet breakup regime, satellite droplets are formed trailing the initial moving droplet. We find such droplet satellite formation is easier with increasing fibre curvature (smaller fibre radius). Finally, in the droplet oscillation regime, favoured in the mid-range of fibre radius, the droplet shape periodically extends and contracts along the fibre.