Friday, May 16, 2008

Whales Inspire New Efficient Blade Technology

He discovered that these bumps, called tubercles, are this creature's secret weapon, allowing a whale the size of a school bus to make tight turns and capture prey with astonishing agility.

To understand this phenomenon, imagine airplane wings. Pilots increase the angle of the airfoil to provide more lift. But when the angle gets too steep, the air current drags on the wing, suddenly reducing the lift and causing the aircraft to stall.

Fish found that humpback fins act a little differently. He and his colleagues tested a scale model of the whale flipper in a wind tunnel. To their surprise, the experiments revealed that significant drag occurs at a much steeper angle on the humpback fin than it does on a sleek flipper. Each tubercle redirects and channels air over the flipper, creating a sort of whirling vortex that actually improves lift, Fish says.

"These bumps were thought of as anatomical anomalies, but they do modify the flow and they do it in ways that are beneficial to the whale," says Fish.

The technology can be used in a huge range of machines such as turbines, compressors, pumps, and fans that use blades or rotors – most anything that cuts through air, water, steam or oil, says Fish.

"There was a 20 percent drop in energy use, a significant drop in noise decibels, and overall distribution of air was more even," says Envira-North CEO Monica Bowden. The increased efficiency also means the new fans will have five blades instead of 10, making them cheaper to manufacture.

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