Volatility-dependent damping of evaporation-driven B\'enard-Marangoni instability

TL;DR

This paper investigates how evaporation and vapor composition influence the onset of Marangoni convection at liquid interfaces, introducing a new dimensionless number to quantify damping effects and validating a model across various evaporation rates.

Contribution

It introduces a novel dimensionless number to quantify damping of interfacial temperature fluctuations and experimentally studies the crossover in Marangoni instability conditions.

Findings

Critical conditions match the nonlocal model predictions.

Damping effects depend on vapor composition and evaporation rate.

The model accurately predicts the transition across different regimes.

Abstract

The interface between a pure liquid and its vapor is usually close to saturation temperature, hence strongly hindering any thermocapillary flow. In contrast, when the gas phase contains an inert gas such as air, surface-tension-driven convection is easily observed. We here reconcile these two facts by studying the corresponding crossover experimentally, as a function of a new dimensionless number quantifying the degree of damping of interfacial temperature fluctuations. Critical conditions are in convincing agreement with a simple nonlocal one-sided model, in quite a range of evaporation rates.