Unsteady fluid fragmentation
Despite the complexity and diversity of modes of unsteady fluid fragmentation into secondary droplets, universality across geometry and fluid systems emerges. We discuss the role of unsteadiness in shaping a ubiquitous, yet neglected class of fluid fragmentation problems based on recent joint experimental and theoretical investigations. In particular, we reveal how unsteadiness and multi-scale dynamics couple to select both the sizes and speeds of secondary droplets generated.