Viscous coalescence of droplets: a Lattice Boltzmann study

TL;DR

This study uses Lattice Boltzmann simulations to analyze viscous droplet coalescence, revealing a t^{1/2} scaling law for the bridge radius that differs from existing theories and experiments.

Contribution

It provides new simulation-based insights into viscous droplet coalescence, challenging existing analytical models and offering a simple scaling explanation.

Findings

Bridge radius follows t^{1/2} scaling in viscous regime

Results differ from existing theories and experiments

A simple scaling argument describes the findings

Abstract

The coalescence of two resting liquid droplets in a saturated vapor phase is investigated by Lattice Boltzmann simulations in two and three dimensions. We find that, in the viscous regime, the bridge radius obeys a t^{1/2}-scaling law in time with the characteristic time scale given by the viscous time. Our results differ significantly from the predictions of existing analytical theories of viscous coalescence as well as from experimental observations. While the underlying reason for these deviations is presently unknown, a simple scaling argument is given that describes our results well.