Stable formations and hydrodynamics of bio-inspired fish schools

Fish that swim in schools have considerable energy savings compared to an isolated fish. This has inspired interest in the development of fish-inspired bio-robots that can be used for underwater surveillance and environmental monitoring. We present experiments conducted using a novel free swimming air bearing platform that allow a pair of tuna-inspired robots to swim side-by-side and independently in the streamwise direction. We observe that fish swimming in schools adopt stable formations and swim faster with an improved cost of transport. Stable school formations are found to be driven by body-to-body interactions. A comprehensive parameter space of mismatched amplitudes, lateral body spacing, and phase synchronization is examined to identify the optimum conditions for stable school formations and improved energetics.