Joséphine Van Hulle (Liège Université)

Droplet dynamics on curved substrates

Understanding the dynamics of droplet motion on curved substrates is crucial for optimizing water collection technologies, particularly in environments where atmospheric water harvesting is essential. We experimentally investigate the behavior of droplets on various macroscopic structures, including vertical cylindrical fibers and conical fibers. Through experimental observations, the research reveals that factors such as fiber twists, gradient radii and pre-existing wetting conditions significantly influence droplet spreading, dynamics and shape transitions. Specifically, the descent of droplets along vertical fibers is characterized by a self-supply mechanism, where the liquid film left behind the droplet contributes to the formation of subsequent droplets. On twisted fibers, droplets follow a helical path governed by the groove geometry. Droplets on conical fibers spontaneously move towards the base of the cone, with their dynamics influenced by their shape. The findings of this work contribute to the design of more efficient substrates for droplet drainage, offering practical applications in the development of optimized fog collectors composed of fiber meshes.