Article published in Annual Review of Fluid Mechanics!

Title: Secondary Atomization of Droplets at Extreme Conditions

Authors: Saini Jatin Rao and Saptarshi Basu

Link: https://doi.org/10.1146/annurev-fluid-112823-115348

Summary: 

From raindrops to sprays in industrial processes, droplet formation is everywhere. But what really happens when a droplet “breaks up” in extreme airflow conditions?

In our latest review article published in the Annual Review of Fluid Mechanics, we explore these fascinating events. When exposed to intense flows, droplets undergo intricate interfacial dynamics—unstable waves and evolution through a cascade of increasingly finer deformations—eventually fragmenting into countless smaller droplets through self-similar processes.

What makes real-world scenarios even more challenging? Droplets often face nonuniform, unsteady, or even compressible flows—like shock waves—which create truly extreme conditions. Our review compares the spatiotemporal scales of such external disturbances and the droplet’s response, highlighting when and how fragmentation occurs. Intriguingly, we find that at very high Mach numbers, compressibility can actually suppress droplet breakup.

Curious about how these micro-scale cascades impact high-tech sprays in everything from aerospace to energy applications? Check out the full story in our review.