Droplets in turbulence

In the turbulent clouds above our heads, small water droplets are whirred around. They collide and merge and in this way may become large enough to make rain. These collisions are enhanced by preferential concentration. Turbulent flows mix added material extremely efficiently. This is what we use if we stir milk in our cup of tea. However, when heavy particles (droplets) are dispersed in a turbulent flow, turbulence creates clusters: preferential concentration.

The research is about new experimental techniques to study clustering at the smallest turbulent length scales, to study collisions between droplets, to study the way they are torn apart in the flow, and to find new numerical techniques to compute their tortuous paths in turbulence.