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Title: Dolphin boundary layer

Description: Explanation:

James Gray, an English Zoologist discovered that dolphins managed to attain speeds in the water that exceeded the power limit calculated for their muscles by a factor of seven. This paradox led researchers to investigate what phenomena accounted for this apparent discrepancy between hydrodynamic theory and physical observation.

While some have questioned Gray's calculations, others like Jim Rohr at the University of California in San Diego have sought answers to this paradox by studying the fluid dynamics. Using bioluminescent dinoflagellates as visual signals and enhanced video recording equipment, he was able to assess the boundary layer over the dolphins body surface at speeds of 2 m/s. These organisms give off light when the fluid layers around them are subject to stresses .wall.0.1Nm.2. He then studied the enhanced recordings and proposed a solution to Gray's paradox. Research revealed that the dinoflagellates failed to light up in regions on the dolphin's body where the boundary layer is thinner. He concluded that their shape creates an optimal boundary layer for greater speeds with less energy.



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