RAISE: Breaking the Surface: The Underlying Fluid-Structure Interactions of Aquatic-Aerial Transition and Stable Locomotion at the Interface

Flying fish are pelagic fish capable of aerial and aquatic locomotion. Using a unique yet understudied taxiing maneuver, the fish dips only the tail fin below the water surface to produce enough speed for takeoff. Repeating this maneuver can extend their glide up to 400 meters without reentering the water. No other organism can perform such a feat. The goal of this research project is to uncover the governing physics that enables flying fish to taxi and take off at the water-air interface. Knowledge gained from this work looks to offer new insights into the locomotion of flying fish to inform the design of innovative engineering systems capable of repeatable and stable aquatic-aerial transitions and operations. Engineering systems with such capabilities can help with environmental monitoring and climate-weather interface sampling applications The project requires concurrent advances in biological science, fluid dynamics, and system dynamics to yield the fundamentals of taxiing locomotion mechanics, understand the environmental effects on such mechanics, and investigate the dynamics and stability criteria of the taxi-to-glide transition. Wing-finned aquatic-aerial locomotion exploits unsteady aerodynamic and hydrodynamic forces, in-ground effect operations, and various fluid-structure interaction mechanisms for stability and control. Using a comparative biomechanics approach, the underlying physics and critical anatomical features that enable such a unique locomotion feat intend to be attained. A novel robotic model organism plans to be designed with such features that will serve as a research tool to test key biological hypotheses and advance the design of mechanical systems that can exploit the water-air interface for locomotion. Informed by field and laboratory measurements on the flying fish and the robotic model organism, the research aims to discover the fluid mechanics that enable aquatic-aerial locomotion and develop multi-body dynamics models to determine the stability and control criteria necessary for repeatable transitions and extended operations at the water-air interface. The physics-informed engineering approach can pave the way for developing a framework for designing mechanical systems capable of taxiing and taking off, presenting a paradigm shift away from ad-hoc design processes and toward model-enabled design. This Research Advanced by Interdisciplinary Science and Engineering (RAISE) grant is jointly funded by the Dynamics, Control and Systems Diagnostics (DCSD) and Physiological Mechanisms and Biomechanics (PMB) programs. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.