A whale of a wind turbine

According to conventional wisdom, things that need to move efficiently through air or water should be sleek and streamlined. Dolphins, jets and speed skaters stick to this rule, but humpback whales, with their massive knobby-edged flippers, buck the trend.

Flipper bumps, called tubercles, are unique to humpbacks. For decades, scientists thought tubercles were a hydrodynamic anomaly until biologist Frank Fish, from West Chester University in Pennsylvania, stuck a four-meter-long flipper collected from a deceased beached whale in a wind tunnel and discovered humpbacks are on to something: The flipper was amazingly aerodynamic.

Humpbacks are the most maneuverable of the large whales, says Fish. Their spectacular breeches make them a favorite among whale watchers and their bulk-defying underwater agility enables them to catch bigger, faster prey than other whales. It turns out their funny bumps are the key to the 30- ton whale’s acrobatics skills, Fish and colleagues say in their paper published May 6 in the journal Integrative and Comparative Biology. The tubercles channel water over the flipper in such a way as to prevent stall — the loss of forward movement — which allows the whales to turn deftly and move efficiently underwater, says Fish.

Fish’s discovery is changing the way engineers think about aerodynamic design. Whalepower, a Toronto-based company, is redesigning wind turbine blades with a humpback-inspired bumpy leading edge. The new “Tubercle Technology” blades produce more energy more efficiently than conventional smooth blades. So far the bumpy blades are still in the testing phase, but Stephen Dewar, head of research and development, says, “The energy production from these blades is extraordinary.” Whalepower hopes to finish testing and begin production within the next year. At least 10 wind power companies have already shown interest in the new blades, with good reason. Dewar says, “These might prove to be the most efficient turbine blades ever made.”

Mary Caperton Morton

William Rossiter	Whalepower
Humpback whales flout conventional streamlined hydrodynamics by sporting anywhere from nine to eleven tubercle bumps along the front edge of their flippers.	A Whalepower “Tubercle Technology” turbine blade.

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