Experimental Comparison of a Passively Self-Actuating Underwater Device Based on a Streamlined Hydrofoil

This study aims to implement a fully passive actuation mechanism for an underwater device. The system utilizes the flow in a water circulating channel and applies a streamlined hydrofoil capable of operating under varying flow conditions. Compared to conventional NACA-series hydrofoils, the elliptical hydrofoil exhibits lower efficiency and operates within a different range of reduced frequencies. On the other hand, it was found to autonomously activate even at relatively low flow velocities and regardless of its initial orientation. In future work, we plan to incorporate a biomimetic fin onto the hydrofoil to passively induce variations in hydrodynamic forces, thereby eliminating the need for mechanical springs.