On 27/3/08 1:27 AM, "Michael Derry" <[EMAIL PROTECTED]> wrote: John Roake: His reply hereunder:
THIS FROM THE JANUARY ISSUE OF GLIDING INTERNATIONAL SHARK SKIN RESEARCH COULD REDUCE SAILPLANE DRAG BY 30 PERCENT It may seem obvious that the surface of an airplane should be as smooth as possible to minimize aerodynamic drag, but that¹s not really the case. A bit of roughness can break up the boundary layer and improve efficiency. Sharks, with skin formed of rough scales called denticles, can slip through the water at speeds of up to 60 mph with minimal drag. This week, The Lindbergh Foundation awarded a grant to Dr. Amy Lang, at the University of Alabama, to study whether the surface texture on the skin of fast-swimming sharks, capable of bristling their scales when in pursuit of prey, could be mimicked and used to reduce the drag on sailplanes. ³If we can successfully show there is a significant effect, future applications to reduce drag of sailplanes and underwater vehicles could be possible,² said Lang. The technology has the potential to increase aerodynamic efficiency up to 30 percent, with savings of billions of dollars and substantial reductions in aircraft fuel burn and emissions. Dr. Lang will perform water-tunnel experiments to measure the flow over and within a bristled sharkskin model (2 cm size scales), which achieves similarity with real sharkskin (0.2 mm size scales) by a corresponding scale down in velocity of the experiments. She will also obtain drag measurements over a sharkskin model in a Couette flow facility containing high-viscosity oil. Her work is also supported by the National Science Foundation. JOHN, EDITOR, GLIDING INTERNATIONAL > In the news today there is much mention of swimmers using hi-tech suits > rather than swimming in brief costumes to improve their times. > > Does anyone on this list know much about this subject and is there any > relevance from what these people have learned that can help us to > improve the performance of our gliders ? > > Michael Derry > _______________________________________________ > Aus-soaring mailing list > [email protected] > To check or change subscription details, visit: > http://lists.internode.on.net/mailman/listinfo/aus-soaring
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