GALCIT Colloquium

The fragmentation of air-liquid interfaces, leading to the formation of droplets of a range of sizes and speeds, plays a critical role in a wide range of engineering and biophysical systems. For many disease transmission applications, transport enabled by the emission of droplets fundamentally shapes the degree and severity of contamination. Examples are found in respiratory exhalations and wetted leaves for foliar diseases relevant to agriculture. A crucial mechanism initiating the liquid fragmentation process is the hydrodynamic instabilities triggered by impulsive forcing, which perturb and disrupt an air-liquid interface. We combine theoretical, numerical, and experimental approaches to investigate a variety of impulsive interfacial flows responsible for drop formation. In these cases, we discuss how liquid fragmentation occurs due to unsteady shearing, droplet splashing and stretching.