College of Engineering News • Iowa State University

Investigating the Owl to Develop New Technology

Anupam Sharma earns NSF CAREER award to study the silent flight of the owl.

As new inventions fill our skies, from wind turbines whirling in an open field, to unmanned aerial vehicles scurrying around the city delivering packages, to planes buzzing 35,000 feet overhead, that new technology can pose a noisy problem.

Anupam Sharma, an assistant professor in the Department of Aerospace Engineering at Iowa State University, is turning to an unusual source to make technology quieter. Sharma is researching nocturnal owls, specifically the Barn owl (Tyto Alba), to understand what makes the bird so quiet during flight, and use bio-inspiration to develop nearly silent aircraft, UAVs, and wind turbines.

The Barn owl is known for its amazingly silent flight. It is so quiet that you cannot hear it until it is only three meters away. While the ability of the owl to fly silently has been known, the physical mechanisms behind it are not. That is what Sharma and his team are planning to research. The team has acquired multiple owl wing specimens to analyze the owl wing anatomy and plumage characteristics.

The plumage of the owl has three unique characteristics that Sharma and his team will be investigating.

Owl Wing_Sharma
(Click to enlarge)

“First, if you look at the leading edge (front part) of the wing, you can see a fine, comb-like structure,” Sharma explained. “if you look at the trailing edge, there is a soft, fringe structure. And finally, if you look under a microscope, the hairs on the feathers rise up vertically and then plateau, giving it a canopy type structure.”

These three features are unique to the owl and are believed to be responsible for its acoustic stealth. Sharma and his team are using state-of-the-art computational techniques and experiments in the anechoic chamber at ISU to investigate these features.

Success in the proposed research can have a transformative effect on a wide range of industries. “One thing that almost everyone is ignoring is noise from unmanned aerial vehicles,” Sharma said. “In the near future, they will be everywhere – assisting with surveillance, farming, delivery, etc. Noise from these vehicles is going to be an issue that needs to be tackled right now.” Sharma believes that the owl-inspired technology can also be scaled up for use in wind turbines and jet engines.

Sharma received a CAREER award for $500,000 from the National Science Foundation and will spend the next five years pursuing this research.