Observing Walking Fluid Droplet Dynamics

Over the summer of 2023, I spent most of my days in the Bush Applied Math Lab within the MIT department. My work involved observing and studying the “walking” behaviours of droplets. Turns out, when a thin layer of oil is vibrated quickly enough, small droplets will bounce over the oil’s surface, propelled by their own wave patterns in so-called “pilot-wave” dynamics.

My work mostly involved running experiments with our vibrating baths and tracking the resulting droplet movement. We set up experiments with drops free to move in circular baths and tracked their motion with a high-speed camera placed overhead. These droplets move around in occasionally interesting shapes from simple orbits to more complex patterns. We still don't fully understand the complex fluid mechanics at play in these systems, but it is speculated that our little bouncing droplets may serve as quantum-mechanical analogues due to their pilot-wave properties. If you ever get the chance to meet with Professor John Bush, he will very excitedly discuss this with you for hours.