Making droplets glow in turbulence

Particle- and droplet-laden flows occur in many natural and industrial processes. To probe their dynamics at high particle concentration we use phosphorescent droplets that can be tagged with a laser. Only the tagged droplets emit light, so that subsets of particles can be selected inside a dense cloud. In our proof of concept experiments we obtain statistical information about the droplet distribution in space, and observe their clustering dynamics in a time period that spans a few turnovers of the smallest eddies in turbulence.