Video: Maple Seeds Ride Self-Generated Tornadoes
- 2:04 pm |
High-speed video reveals that maple seed pods remain airborne for miles by harnessing the power of tornado-like vortexes generated as they spin.
The flat, elongated pods are densest at their seed-containing ends, a configuration that causes them to rotate while falling.
Rotation produces the pods’ nickname — whirlybirds — and creates tiny vortexes above their leading edges. By pulling in air, a vortex lowers air pressure above a pod’s surface, effectively sucking it upwards.
The dynamics of this elegant process are described Thursday in Science by researchers who took three-dimensional flow readings of oversize plastic whirlybird models spinning through a laser-lit solution of glass beads suspended in oil and then, to validate these models, of real pods falling through smoke.
According to the researchers, the pods are fully twice as aerodynamic while falling, and more efficient than standard aircraft wings and helicopter blades. Such vortexes are also found in hovering insects and bats, and may represent “a convergent aerodynamic solution in the evolution of flight performance in both animals and plants.”
This solution could eventually inform the design of micro-helicopters and parachutes attached to planet-exploring robotic probes, raising the rather delicious possibility of humanity spreading through space like so many whirlybirds carried on a spring breeze.
- Secret Law of Flying Could Inspire Better Robots
- Video: Leaping Lizard’s Tail-Free Mid-Air Wipeout
- The Magic of Mushroom Spores
Citation: “Leading-Edge Vortices Elevate Lift of Autorotating Plant Seeds.” By D. Lentink, W. B. Dickson, J. L. vanLeeuwen, M. H. Dickinson. Science, Vol. 324 Issue 5933, June 12, 2009.
Video & Image: David Lentink