Hi guys, thought you might be interested in this.... Kevortex
03/24/08 - Humpback flipper based Wind Turbines
A new type of wind-turbine blade that mimics the aerodynamic performance of a humpback whale's flipper, allowing a turbine to capture more of the wind's energy at much lower speeds. The odd-looking blades, which have teeth-like bumps along their leading edge, are a dramatic departure from the smooth and sleek design that graces most wind turbines. It turns out the key to a humpback's agility lies in its long flippers, which feature a unique row of bumps or "tubercles" along their leading edge that give the wing-like appendages a serrated look. Researchers such as Frank Fish, a professor of biology at West Chester University in Pennsylvania, have found that the tubercles dramatically increase the whale's aerodynamic efficiency. In one particular study conducted inside a controlled wind tunnel, Fish and research colleagues at Duke University and the U.S. Naval Academy saw 32 per cent lower drag and an 8 per cent improvement in lift from a flipper with tubercles compared to a smooth flipper found on other whales. They also discovered that the angle of attack of the bump-lined flipper could be 40 per cent steeper than a smooth flipper before reaching stall - that is, before seeing a dramatic loss in lift and increase in drag. In an airplane scenario, that's typically when you lose control and crash. "That stall typically occurs on most wings at 11 or 12 degrees at the angle of attack," says Fish, adding that with the humpback design "stall occurred much later, at about 17 or 18 degrees of attack. So the stall is being delayed." The implications are potentially enormous. Delayed stall on airplane wings can improve safety and make planes much more manoeuvrable and fuel-efficient. The same benefits can also be found on ship and submarine rudders, which explains the U.S. Navy's quiet involvement.
Old news, consensus seems its not DIY or practical
