Waltz of tiny droplets and the flow they live in

This article describes the dynamics of small inertial particles centrifuging out of a single vortex. It shows the importance of caustics formation in the vicinity of a single vortex: both for particle collisions and void formation. From these single-vortex studies we provide estimates of the role of caustics in high Reynolds number turbulence, and in the case of clouds, estimate how they may help in rain initiation by bridging the droplet-growth bottleneck. We briefly describe how the Basset-Boussinesq history force may be calculated by a method which does not involve huge memory costs, and we provide arguments for its possible importance for droplets in turbulence. We discuss how phase change could render cloud turbulence fundamentally different from turbulence in other situations.

Automated summary

This article investigates the dynamics of small inertial particles centrifuging out of a single vortex. It highlights the importance of caustics formation near a single vortex for particle collisions and void formation. The study provides estimates of the role of caustics in high Reynolds number turbulence and its potential impact on rain initiation in clouds. Additionally, it discusses the calculation of the Basset-Boussinesq history force and its possible significance for droplets in turbulence, as well as how phase change can affect cloud turbulence differently from turbulence in other situations.