Clogging of cohesive oil droplets in a 2D hopper

We present an experiment studying the flow of microscopic monodisperse cohesive oil droplets through a two-dimensional hopper. We vary the size of the hopper opening, the size of the droplets, the effective buoyant force which drives the droplets to flow, and the cohesion between droplets. In our experiments, we find that the cohesive strength is positively correlated to the probability of clogging. We compare a range of cohesion strengths and define a parameter balancing the relevant forces of buoyancy and cohesion, which can be used to describe the process of clogging.