Splashing onset in dense suspension droplets

TL;DR

This paper introduces a particle-based Weber number to predict splash onset in dense suspension droplets, replacing traditional hydrodynamic models, and explains particle escape behavior in bimodal systems.

Contribution

It proposes a new energy balance at the particle level to accurately predict splash onset, validated through experiments, improving understanding of dense suspension impacts.

Findings

Particle-based Weber number reliably predicts splash onset.

Smaller particles are more likely to escape in bimodal systems.

Energy balance at particle level explains splash behavior.

Abstract

We investigate the impact of droplets of dense suspensions onto a solid substrate. We show that a global hydrodynamic balance is unable to predict the splash onset and propose to replace it by an energy balance at the level of the particles in the suspension. We experimentally verify that the resulting, particle-based Weber number gives a reliable, particle size and density dependent splash onset criterion. We further show that the same argument also explains why in bimodal systems smaller particles are more likely to escape than larger ones.