We use a drop-on-demand system (as in inkjet printers) to generate controlled droplet trains with tunable speed, spacing, and number of drops. This allows us to ask how the presence of neighboring droplets affects the motion of an individual drop, and whether a droplet train travels faster and farther than an isolated droplet.
Recent work shows that the ballistic aggregation of such droplet trains is governed by a single length scale, which sets the scaling of cluster growth and the travel distance of the train. In related spray experiments, we find that ambient air pressure controls the formation and extent of spray clouds, linking the macroscopic spray structure to the surrounding gas environment.
On the jet side, we have shown that the breakup length of capillary jets is set by intrinsic thermal capillary waves rather than external noise or nozzle imperfections, providing a unified description of jet breakup from nanojets to faucet-sized streams.
Together, these projects connect single-drop dynamics, droplet–droplet interactions, and jet breakup to the formation and propagation of sprays.
Contact: Daniel Bonn (d.bonn@uva.nl)