Using lasers and a water tank, an engineer hopes to use secrets gleaned from the aerodynamically unconventional flights of hummingbirds and other tiny birds and insects to help design tiny self-propelled flying surveillance devices. The research could also have biomedical and energy applications. Instead of the streamlined flow that occurs when air flows over the wing of a jet, fluid dynamics at the much smaller scale of hummingbird wings are characterized by a swirling, looping flow of air called a vortex, similar to that which is created by canoe paddles as they are pushed through the water. These aerodynamically unconventional flows are the inspiration behind new research by a University of Buffalo scientist who hopes to understand the nature of the 3-D vortex formation process so that it can be optimized. To better understand how a 3-D vortex forms, Matthew Ringuette and colleagues are conducting experiments using lasers and rectangular flapping “wings” in a water tank. The team is working to develop flying devices on the scale of just a few inches, which requires a much greater understanding of the propulsion systems of tiny birds and insects. (Photo: University of Buffalo)The research by Matthew Ringuette, assistant professor in the department of mechanical and aerospace engineering in the University of Buffalo School of Engineering and Applied Sciences, is motivated by the need to gather real-time intelligence in particularly challenging environments, such as in remote caves and tunnels or complex building corridors in cities, neither of which can easily be penetrated by conventional, unmanned aircraft or spy satellites. “In surveillance applications, these small, autonomous or remote-controlled vehicles would be ideal because they would be able to penetrate these complex kinds of terrain and gather first-hand, real-time intelligence,” Ringuette said. But developing flying devices on the scale of just a few inches requires a much greater understanding of the propulsion systems of tiny birds and insects. “When you get down to such small sizes and slow speeds, conventional aerodynamics no longer apply,” he said. “Animals, such as insects and birds, take advantage of this vortex formation to achieve flight and outstanding maneuverability,” he said. Ringuette’s research is designed to discover how vortex growth and development scales with wing size, motion and shape, so that the wing of a micro-air vehicle can be optimized for maximum propulsive force and efficiency. He notes that this work is fundamental to 3-D vortex formation in general, which occurs in a variety of settings, from cardiovascular flows to wind-energy applications.He will conduct experiments using a robotic, flapping-wing model that will propel itself through a water tank 13 × 4 × 3 ft in his Vortex Dynamics and Bio-Inspired Propulsion Lab at the University of Buffalo. In water, these flapping wing models can produce at larger scales vortex formation similar to that exhibited by birds and insects. Ringuette will be making quantitative measurements of wing flow velocity and the forces at work during propulsion, supplemented by dye visualization to obtain a picture of the 3-D flow. Ringuette is conducting this research as a result of his Young Investigators Research Program award from the Air Force Office of Scientific Research. For more information, visit: www.buffalo.edu