Meeting Abstract

52.3  Monday, Jan. 5  Leading edge vortices elevate lift of autorotating plant seeds LENTINK, David*; DICKSON, William B.; VAN LEEUWEN, Johan L.; DICKINSON, Michael H.; Wageningen University; California Institute of Technology; Wageningen University; California Institute of Technology david.lentink@wur.nl

As they descend, the autorotating seeds of maples and some other tree species generate exceptionally high lift, but how they attain this elevated performance is unknown. To elucidate the mechanisms responsible, we measured the three-dimensional flow around dynamically-scaled models of maple and hornbeam seeds. We show that these seeds attain high lift by generating a stable leading edge vortex (LEV) as they slowly descend. The compact LEV of maple seeds allows them to remain in the air more effectively than do a variety of non-autorotating seeds. LEVs also explain the high lift generated by hovering insects, bats, and possibly, hummingbirds. This suggests that the use of LEVs represents a convergent aerodynamic solution in the evolution of flight performance in both animals and plants.