DURHAM, N.C. -- Wind tunnel tests of scale-model humpback whale flippers have revealed that the scalloped, bumpy flipper is a more efficient wing design than is currently used by the aeronautics industry on airplanes. The tests show that bump-ridged flippers do not stall as quickly and produce more lift and less drag than comparably sized sleek flippers.

The tests were reported by biomechanicist Frank Fish of West Chester University, Penn., fluid dynamics engineer Laurens Howle of the Pratt School of Engineering at Duke University and David Miklosovic and Mark Murray at the U.S. Naval Academy. They reported their findings in the May 2004 issue of Physics of Fluids , published in advance online on March 15, 2004.

In their study, the team first created two approximately 22-inch-tall scale models of humpback pectoral flippers -- one with the characteristic bumps, called tubercles, and one without. The models were machined from thick, clear polycarbonate at Duke University. Testing was conducted in a low speed closed-circuit wind tunnel at the U.S. Naval Academy in Annapolis, Md.

The sleek flipper performance was similar to a typical airplane wing. But the tubercle flipper exhibited nearly 8 percent better lift properties, and withstood stall at a 40 percent steeper wind angle. The team was particularly surprised to discover that the flipper with tubercles produced as much as 32 percent lower drag than the sleek flipper.

"The simultaneous achievement of increased lift and reduced drag results in an increase in aerodynamic efficiency," Howle explains.

This new understanding of humpback whale flipper aerodynamics has implications for airplane wing and underwater vehicle design. Increased lift (the upward force on an airplane wing) at higher wind angles affects how easily airplanes take off, and helps pilots
'"/>

Contact: Deborah Hill
dahill@duke.edu
919-401-0299
Duke University
11-May-2004

Page: 1 2 3
Related biology news :

1. Study: Mimicking viruses may provide new way to defeat them
2. Mimicking the human body with carbon black polymers
3. Mimicking a human disease in mice
4. South Dakota Tech grad student finds rare whale
5. Evolution of whale hearing unfolds in fossil record
6. Ocean scientists assess impact of seismic pulses in effort to protect whales
7. Research into cetacean reproduction leads to birth of killer whales by artificial insemination
8. News tip: Duke marine biologist calls for whale-proof fishing gear
9. Climate linked to reproduction of right whales
10. Collapse of seals, sea lions & sea otters in North Pacific triggered by overfishing of great whales
11. Seeking the cause of a mysterious whale disease