Daniel Bonn, Institute of Physics, University of Amsterdam

I will discuss the formation and breakup of liquid sprays with an emphasis on the underlying instability mechanisms and their consequences for droplet-size statistics. I will mainly focus on medical sprays (e.g., nose sprays or asthma medication) formed by collections of Rayleigh jets. In a simplified one-dimensional jet geometry we first study the breakup length of a jet and subsequently resolve the full coalescence dynamics of droplets and ligaments. For multiple jets forming a spray cloud, I will discuss how these can be understood and show how  vacuum can be used to suppress the Kelvin–Helmholtz instability that leads to the characteristic fanning out of the spray cloud.