Saptarshi Basu, Indian Institute of Science (IISc), Bengaluru, India

Abstract

Droplets are silent protagonists in many natural and engineered settings – from raindrops and ocean sprays to fuel injection in turbines, microfluidic chips and even the aerosols that shaped recent pandemics. Despite the diversity of these contexts, the "autobiography" of a droplet is guided by a set of universal physical principles. This colloquium will take the audience on a journey across these domains, uncovering how droplets evaporate, deform, fragment, and interact with their surroundings under a wide spectrum of flow conditions.

The adventure finally leads us to the phenomenon of aerobreakup – the disintegration of a droplet exposed to high-speed gas flows. This process unfolds as a cascade of multiscale deformations, illustrating interfacial instabilities, ligament-mediated breakup and dispersed daughter droplets. The talk will further explore how droplets respond under extreme conditions, such as shock waves, where unexpected behaviours emerge.

By blending vivid experiments with fundamental models, we aim to reveal the underlying physics while highlighting its practical implications in technologies that shape our daily lives and future innovations.