When two droplets of simple liquids are gently brought into contact, they merge into a single larger drop to minimize surface energy, a mechanism referred to as coalescence. The situation is markedly different for complex fluids, where finite-size effects, non-local rheology, and complex rheological behavior come into play. By combining ultra-fast imaging techniques, rheology, and image processing, we aim to reveal the mechanisms governing the coalescence dynamics of complex fluid drops.
In parallel, we study the coalescence of simple fluid drops across inertial and viscous regimes. Recent work has established a simple crossover function that captures the transition between inertial and viscous dynamics during drop–drop coalescence, and has clarified the very early stages of neck formation, highlighting the roles of the surrounding gas and van der Waals forces in initiating and shaping the coalescence process.
Contact: Daniel Bonn (d.bonn@uva.nl)