Understanding Owl's Noiseless Flight Could Help Design Near-Silent Aircrafts, Researchers Say

Scientists are now trying to understand the mechanism that enables owls to fly noiselessly during night. The research may pave way for a new generation of silent aircrafts, turbines and submarines.

Researchers at University of Cambridge and Lehigh University are now investigating how the soft feathers muffle noise while flying in owls.

"Owls possess no fewer than three distinct physical attributes that are thought to contribute to their silent flight capability: a comb of stiff feathers along the leading edge of the wing; a flexible fringe a the trailing edge of the wing; and a soft, downy material distributed on the top of the wing," explained Justin Jaworski, assistant professor in Lehigh University's Department of Mechanical Engineering and Mechanics.

Previous work by Jaworski and Nigel Peake at the University of Cambridge has revealed that the owl's wing is designed to reduce noise. The feathers atop an owl's wings create a soft carpet that eliminates sounds. The mechanism by which this cushion cuts off noise is very different from the usual sound absorbers.

Ian Clark of Virginia Tech carried out photographic analysis of owls' wings and found that they possess surprising 'forest- like' geometry. Scientists will now be using this geometric pattern in their future research. Virginia Tech researchers have already invented a simple mesh-like structure covered by material that mimics this forest structure to eliminate noise.

The latest research on owls' wings was presented at the meeting of the American Physical Society's (APS) Division of Fluid Dynamics.

"If the noise-reduction mechanism of the owl down can be established, there may be far-reaching implications to the design of novel sound-absorbing liners, the use of flexible roughness to affect trailing-edge noise and vibrations for aircraft and wind turbines, and the mitigation of underwater noise from naval vessels," said Jaworski in a press release.