When Can a Leak Stop Itself?

Despite the abundance of liquid rivulets in both nature and industrial applications, much remains unknown about how, why, and when they destabilize. In this work, we characterize a liquid leaking from a small hole that can exhibit a range of flow behaviors including jetting, continuous rivulet flow, discrete dripping, and spontaneous arrest. Here, we study flow transitions into and out of the rivulet regime, with particular focus on the mechanisms of rivulet destabilization and breakup en route to spontaneous arrest of the leaking flow. By exploring a broad range of parameter space including varying inlet diameter, wetting contact angle, and axial flow rate, our experiments allow us to map out the various outcomes associated with end pinching and Rayleigh-Plateau-like instabilities, both of which play a role in the transition toward spontaneous self arrest of small fluid leaks.