Capturing the wonders of hummingbird flight
Simulations illustrate swirling air currents around birds’ wings
AIR SET ASWIRL Small pockets of air circulate around a hummingbird’s wings in this image from a computer simulation of flight.
Yan Ren, Haibo Dong, Xinyan Deng, B. Tobalske (CC BY-NC 4.0)
Hummingbirds are extreme athletes, deftly hovering and darting between flowers. Now a combination of high-speed filming and computer simulations reveals how the birds’ wings manipulate the surrounding air to aid in flight. The images seen here come from a video of simulated flight that won an American Physical Society Gallery of Fluid Motion award in November.
Above, small pockets of air swirl in tornado-like vortices as a hummingbird turns to its right. Researchers have known that the bird’s wings induce lift by generating what are called leading-edge vortices (represented as thick blue layers around the wing edges). But the air movement is even more complex, the simulations reveal. The sequence of images below, which display only the largest vortices, shows how a bird in flight spawns an array of helpful swirls near different parts of the wings. Blue pockets of air are circulating in the opposite direction of red pockets.
These vivid depictions of hummingbird flight incorporate data from the lab of University of Montana biologist Bret Tobalske, who films the birds with cameras shooting at 1,000 frames a second. The simulations help Tobalske dissect how the birds use leading-edge vortices in flight, a tactic that has also been mastered by insects and the seed capsules of trees. Other researchers hope to create flying robots that mimic this approach.
FLIGHT SIMULATOR Air flows in tornado-like vortices around a hummingbird’s wings in a computer simulation. This video was honored in November at the American Physical Society’s Fluid Dynamics meeting in Boston.
Yan Ren, Haibo Dong, Xinyan Deng, B. Tobalske (CC BY-NC 4.0)
