Researchers from Cambridge University have found that wind turbines and planes could be much quieter and more efficient if they mimic owls’ flight.

"Many owls can hunt by stealth, swooping down and capturing their prey undetected. While we have known this for centuries, what has not been known is how or why owls are able to fly in silence," says lead researcher professor Nigel Peake.

Peake collaborated with researchers at Virginia Tech, Lehigh and Florida Atlantic Universities and used high-resolution microscopy to examine owl feathers in detail. The team used that information to build a prototype coating for wind turbine blades that could be replicated in other types of fan blades and reduce the amount of noise they make.

"Much of the noise caused by a wing—whether it is attached to a bird, a plane or a fan—originates at the trailing edge where the air passing over the wing surface is turbulent," Peake says. The structure of an owl's wing serves to reduce noise by smoothing the passage of air as it passes over the wing. In effect, it scatters the sound so their prey cannot hear them coming.

The researchers found that owl wings have a flexible comb ofOwl wings have a flexible comb of evenly-spaced bristles on their leading edge and a porous and elastic fringe on the trailing edge. Source: Cambridge, Image credit: J. Jaworski evenly-spaced bristles on their leading edge and a porous and elastic fringe on the trailing edge. With that knowledge, they built a prototype made of 3D-printed plastic and tested it on a full-sized segment of a wind turbine blade.

In tests, the treatment reduced noise produced by wind turbine blades by 10 decibels, reportedly without any noticeable effect on aerodynamics. The new surface also allows the turbines to run at higher speeds.