Maximizing performance of ≥3 in-line oscillating fins

Fin-fin interaction of underwater swimmers is beneficial for swimming performance of schooling animal swimmers and is becoming increasingly utilized in bioinspired propulsion technology. However, there is a lack of research focused on the benefits and possible plateau in performance of in-line fins in underwater propulsion for systems with greater than two fins. Using coupled experiments and immersed boundary simulations, we find the idealized kinematics and spacing of a three fin system, followed by exploring the asymptotic behavior of larger systems. We study fins oscillating in both pitch and heave with variable spacing, phase, amplitude, and frequency. We find the ideal swimming configuration through parameter space exploration and optimization, focused separately on maximizing thrust and efficiency. We find that there are further benefits to be gained by adding more than two fins.