Drift instability in the motion of a fluid droplet with a chemically reactive surface driven by Marangoni flow

TL;DR

This paper develops a theoretical framework for understanding how a chemically reactive droplet driven by Marangoni flow becomes unstable and starts moving, supported by numerical simulations.

Contribution

It derives amplitude equations describing the instability and motion of reactive droplets influenced by Marangoni flow, providing new insights into their dynamics.

Findings

Identifies the critical point for droplet motion onset.

Derives the droplet velocity from nonlinear amplitude equations.

Numerical simulations confirm theoretical predictions.

Abstract

We theoretically derive the amplitude equations for a self-propelled droplet driven by Marangoni flow. As advective flow driven by surface tension gradient is enhanced, the stationary state becomes unstable and the droplet starts to move. The velocity of the droplet is determined from a cubic nonlinear term in the amplitude equations. The obtained critical point and the characteristic velocity are well supported by numerical simulations.