Aside from a wise face, amazing night vision, and deadly flesh-tearing beak, the owl’s killer feature is its silence. If you were a rodent scurrying through what you foolishly assumed to be a sufficiently dark shadow, you wouldn’t hear the owl dropping from the sky. No, the first thing you would hear would be the bones snapping in your own neck.
Researchers at the University of Cambridge have reverse-engineered the design of the owl’s silent wings and applied it to wind turbines, allowing them to cut through the air more quietly, and without sacrificing aerodynamics.
Nigel Peake, a professor in Cambridge’s Department of Applied Mathematics and Theoretical Physics, and his team examined the feathers in owl wings and found a unique structure, consisting of a fluffy covering, and comb-like bristles at the wing’s leading edge.
But the key part is at the back, where a fringe smooths the airflow off the wing. “The structure of an owl’s wing serves to reduce noise by smoothing the passage of air as it passes over the wing–scattering the sound so their prey can’t hear them coming,” says Peake.
Biomimetic designs–human designs that copy nature’s tricks–are everywhere. Velcro, for example, copies burs. hook-covered seeds that latch onto animal fur to disperse themselves.
Peake’s team has tested a 3-D-printed coating that reduces the noise from a turbine blade by 10dB. This could result in quieter wind farms, but it could also allow turbines to spin faster, generating more power, without getting any louder.