Fish schools have inspired the imagination and with it a host of hypotheses for their function ranging from social behaviors and enhanced protection against predators to a reduction in the energetic cost of swimming. Regardless of the prime function, animals in a collective encounter fluid dynamic interactions from their neighbors that may modify their locomotion energetics, force production or force them into a particular arrangement. Yet, we know very little about the unsteady and especially three-dimensional interactions that occur in schools. The goal of our work is to develop an understanding of the flow mechanisms, manipulated through vorticity control, that occur among unsteady, and three-dimensional interacting bodies in complex arrangements. This talk will explore side-by-side and in-line canonical arrangements of swimmers with a blend of computations and experiments. In general, it will be shown that the spacing and synchrony can dramatically alter the performance of swimmers either causing them to have enhanced or diminished thrust and efficiency as compared to swimming in isolation. In addition, fluid-mediated forces also can push or pull these swimmers apart or together and can give rise to stable equilibrium spacings. Finally, three-dimensional effects are shown to significantly alter the interactions between swimmers leading to vortex breakdown and decreasing performance enhancements where two-dimensional models predict the opposite. These findings will enable the development of fast and efficient schools of bio-inspired devices and provide further insight into the dynamics of animals and robots flying and swimming near a free surface, a wall or the ground.
Dr. Keith Moored is an Assistant Professor in the Department of Mechanical Engineering and Mechanics at Lehigh University. He received a B.S. in Aerospace Engineering and a B.A. in Physics at the University of Virginia in 2004, and his Ph.D. in Mechanical and Aerospace Engineering also from the University of Virginia in 2010. From 2010-2013, he was a Postdoctoral Research Associate and Lecturer in Mechanical and Aerospace Engineering at Princeton University. In 2012, he sailed as faculty on Semester at Sea for the Engineering Maymester, short-term voyage through South and Central America. Dr. Moored joined the faculty at Lehigh University in 2013. His research interests are in bio-inspired propulsion, unsteady aerodynamics and fluid-structure interaction. He is currently a PI on an ONR MURI topic of non-traditional propulsion and he has recently received an NSF CAREER award for examining the fluid dynamic interactions among swimmers in a school.