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ReefLady · 12-02-2003, 11:16 AM

Scientists pinpoint how fish save energy by swimming in schools

DECEMBER 1, 2003

" Using a tank designed to mimic a turbulent waterway, scientists have found that fish use a unique and clever swimming motion to harness the energy of eddies in flowing water. By essentially hitching a ride and letting these vortices propel them along, the scientists say, fish can swim against a current with considerably less exertion than is required in calmer settings.

The study provides the first direct view of the technique used by fish to exploit the energy of eddies generated by the swimming movements of other members of a school.

The work, reported in the Nov. 28 issue of Science by researchers from MIT and Harvard, could have many engineering applications, from the design of better fish ladders and passageways at hydroelectric dams to autonomous underwater vehicles capable of negotiating turbulent flows in natural habitats.

“This study reveals mechanisms through which the energy contained in the ed-dies of turbulence can be extracted, with great reduction in the required swim-ming effort,” said Michael S. Triantafyllou, a professor in MIT’s Department of Ocean Engineering. “Since turbulence is present everywhere in moving water or air -- in the ocean, the lakes, and streams, as well as the atmosphere -- many op-portunities arise for engineering applications of these new principles of energy extraction.”

First author James C. Liao, a graduate student in Harvard’s Department of Or-ganismic and Evolutionary Biology, likens the technique fish use to swim against a turbulent current to tacking, the back-and-forth motion that allows a sailboat to move forward passively, if somewhat indirectly, against a breeze."

~*Read the Full Article here*~

12-02-2003, 11:16 AM	#1 (permalink)
ReefLady Golden Moray Join Date: Nov 2003 Location: New Hampshire, USA Posts: 2,031 View Gallery Karma Komment	Scientists pinpoint how fish save energy... Scientists pinpoint how fish save energy by swimming in schools DECEMBER 1, 2003 " Using a tank designed to mimic a turbulent waterway, scientists have found that fish use a unique and clever swimming motion to harness the energy of eddies in flowing water. By essentially hitching a ride and letting these vortices propel them along, the scientists say, fish can swim against a current with considerably less exertion than is required in calmer settings. The study provides the first direct view of the technique used by fish to exploit the energy of eddies generated by the swimming movements of other members of a school. The work, reported in the Nov. 28 issue of Science by researchers from MIT and Harvard, could have many engineering applications, from the design of better fish ladders and passageways at hydroelectric dams to autonomous underwater vehicles capable of negotiating turbulent flows in natural habitats. “This study reveals mechanisms through which the energy contained in the ed-dies of turbulence can be extracted, with great reduction in the required swim-ming effort,” said Michael S. Triantafyllou, a professor in MIT’s Department of Ocean Engineering. “Since turbulence is present everywhere in moving water or air -- in the ocean, the lakes, and streams, as well as the atmosphere -- many op-portunities arise for engineering applications of these new principles of energy extraction.” First author James C. Liao, a graduate student in Harvard’s Department of Or-ganismic and Evolutionary Biology, likens the technique fish use to swim against a turbulent current to tacking, the back-and-forth motion that allows a sailboat to move forward passively, if somewhat indirectly, against a breeze." ~Read the Full Article here~ __________________ ~ Teri -------- "You do not need a parachute to skydive. You only need a parachute to skydive twice."