Splashing of impacting drops

TL;DR

This paper studies the impact velocity threshold for droplet splashing on smooth surfaces, revealing its dependence on liquid surface tension and independence from surface wetting properties, supported by a simplified predictive model.

Contribution

It introduces a simplified analytical formula for predicting splashing velocity, improving understanding of droplet impact dynamics under atmospheric conditions.

Findings

Splashing velocity increases with liquid surface tension.

Splashing velocity is independent of surface wetting properties.

A simplified model accurately predicts splashing velocity.

Abstract

We investigate the impact velocity beyond which the ejection of smaller droplets from the main droplet (splashing) occurs for droplets impacting a smooth surface. We examine its dependence on the surface wetting properties and droplet surface tension. We show that the splashing velocity is independent of the wetting properties of the surface, but increases roughly linearly with increasing surface tension of the liquid. A preexisting splashing model is considered that predicts the splashing velocity by incorporating the air viscosity. The model is consistent with our data, but the calculation is complex. To address this issue, we propose a simplification, assuming atmospheric conditions and low viscosities, and show that the simplification gives an equally good prediction of the splashing velocity from a simple analytical formula.