Looking to owl wings to inspire ideas for quieter aircraft, wind turbines

AMES, Iowa: Anupam Sharma pulled an accordion folder from the bookshelf above his Iowa State University desk. Inside was the carefully collected and preserved wing of a short-eared owl.

Here, he said, could be some clues for developing ultra-quiet aircraft and wind turbines.

“The owl is almost completely silent in flight,” said Sharma, an Iowa State assistant professor of aerospace engineering and Walter W. Wilson Faculty Fellow who started working in aeroacoustics – the noise associated with air flow – during graduate school and a previous position at GE. “Owls are not only silent in gliding flight, but also in flapping flight, which is amazing.”

And then Sharma picked up the wing and pointed out the three-part “owl hush kit” that’s responsible for silent flight.

First, at the leading edge of the wing there are small, fine, comblike structures. Second, all the feathers at the trailing edge of the wing end in a pliable and porous fringe. And third, there’s a downy coat on the flight feathers.

To learn exactly how that hush kit manipulates air flow, turbulence and pressure to produce silent flight, Sharma is scanning owl wing specimens, creating digital models and running multi-day simulations that use more than 16,000 processors provided by one of the country’s top-ranked supercomputing facilities at Argonne National Laboratory in Illinois. He and his colleagues hope their studies will produce practical ideas for making ultraquiet aircraft and wind turbines. — Newswise