Kenny Breuer, School of Engineering
Sharon Swartz, Ecology and Evolutionary Biology
Although the natural world has countless examples of creatures with extraordinary flight capabilities, bats have evolved with truly extraordinary aerodynamic capabilities that enable them to fly in dense swarms, to avoid obstacles, and to fly with such agility that they can catch prey on the wing, maneuver through thick rainforests and make high speed 180 degree turns. Bats possess specialized features that may contribute to their flight performance, including highly articulated and flexible skeletons, flexible and compliant membrane wings, thousands of tiny hair sensors distributed over their wing surface as well as a series of muscles embedded in the wing membrane whose function appears to be the active control of camber during flight. Our multidisciplinary research team consists primarily of researchers from Biology and Engineering and includes significant collaborations with researchers in Computer Science and Applied Mathematics, all working to characterize these unique flight capabilities, to understand the roles that the bats' bones, skin morphology and wing motion all play in enabling this behavior, to model these mechanisms, and ultimately to emulate them in engineered systems.
Unlike insects and birds, both of whom have relatively rigid wings that can move with only a few degrees of freedom, the bat's wing is comprised of a thin, highly compliant skin membrane that is supported on a very flexible jointed skeleton with numerous degrees of freedom. The aerodynamics of flexible, articulated wings is extremely complex and poorly understood, and our team is studying their characteristics using high-speed measurements of the bat's wing and body motion. These kinematic measurements are synchronized with Particle Image Velocimetry (PIV) measurements of the fluid velocity in the wake behind the animal and, together, the kinematic and fluid measurements will shed light on the lift and thrust mechanisms that bats use during straight flight as well as maneuvers. In support of these biological flight experiments, we are performing wind tunnel tests on physical models that mimic features observed in nature, material tests on bat bones and wing membranes, numerical simulations, theoretical modelling and advanced scientific visualizations.
Our research is supported by AFOSR and NSF
Bat wake measured using PIV, from Hubel et al 2009
Some videos from our research
Cynopterus brachyotis (lesser dog-faced fruit bat), fliying the wind tunnel
Tadarida brasiliensis (Mexican free-tail bat), flying in the wind tunnel