Photo by Dave Kemp
Megan Treacy, writing on the care2 website, says one of the most commonly heard complaints about wind turbines is that they're loud. She reports that researchers at the University of Cambridge, have come up with a prototype coating for wind turbine blades that could make them a lot quieter and they owe the advancement to one of nature's greatest hunters, the owl. Owls employ remarkable engineering in their wings, which other birds do not have, that allows them to fly and dive on prey in silence. Much of the noise in any wing originates in the trailing edge because of turbulent air passing over the wing surface. The owl's amazing wings however smooth the passage of the air with a downy covering on a flexible comb of bristles on the leading edge, and most importantly, a porous and elastic fringe of feathers on the trailing edge that dampens sound. Researchers have come up with a porous coating of 3D-printed plastic that might replicate the effect of the owl's fringe that scatters sound. Wind tunnel tests have shown a reduction of 10 decibels. Tests of the coating are planned for operational wind turbines to see if power output can be improved while keeping the noise down. Once again, nature prompts science.
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