Sharks teach researchers how to fly
By Nathan A. Ferguson
With a simple flick of the tail, sharks can accelerate effortlessly through the water. Wouldn't it be nice if airplanes could do the same in the air?
Scientists have long been interested in the unique scales found on sharks that contain ridge-like structures known as riblets. The tiny ridges run parallel to the shark's longitudinal axis and reduce drag by influencing the boundary layer. Thanks to developments in the materials sciences, researchers are getting closer to taking concepts from the natural world and adapting them to commercial applications.
And now aquatic life will get more scrutiny. The Lindbergh Foundation announced on Dec. 3 that it was awarding a grant to Dr. Amy Lang of the University of Alabama. It was one of 14 grants awarded by the foundation so far this year. Lang will determine whether the surface texture on the skin of fast-moving sharks, potentially capable of bristling their scales when in pursuit of prey, can be mimicked and applied to aircraft.
Boeing and Airbus have done their own testing on riblets and found small gains in drag reduction. Researchers have applied special films, manufactured by companies like 3M, to aerodynamic surfaces rather than scoring hard surfaces.
As the Lindbergh Foundation pointed out, even a drag reduction of 1 percent could save an airline $100,000 to $200,000 a year per aircraft. That translates to some 25,000 gallons of fuel. Lang will perform water tunnel experiments using a bristled sharkskin model to unlock keys about how the creatures minimize drag.
Although the airlines have the most to gain from the technology, it may become more attractive to general aviation with the rising fuel prices, especially if aircraft performance can be improved with simple modifications.
December 5, 2007
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