Dolphins get a lift from delta wing technology (6/27/2009)
We can only marvel at the way that dolphins, whales and porpoises scythe through water. Their finlike flippers seem perfectly adapted for maximum aquatic agility. However, no one had ever analysed how the animals' flippers interact with water; the hydrodynamic lift that they generate, the drag that they experience or their hydrodynamic efficiency. Laurens Howle and Paul Weber from Duke University teamed up with Mark Murray from the United States Naval Academy and Frank Fish from West Chester University, to find out more about the hydrodynamics of whale and dolphin flippers. They publish their finding that some dolphins' fins generate lift in the same way as delta wing aircraft on 26 June 2009 in The Journal of Experimental Biology at http://jeb.biologists.org.
Using Computer tomography scanning of the fins of seven different species ranging from the slow swimming Amazon River dolphin and pygmy sperm whale to the super-fast striped dolphin, the team made scaled models of the flippers of each species. Then they measured the lift and drag experienced by the flipper at inclinations ranging from -45deg. to +45deg. in a flow tunnel running at a speed that would have been the equivalent of 2m/s for the full scale fin.
Comparing the lift and drag coefficients that the team calculated for each flipper at different inclination angles, they found that the flippers behave like modern engineered aerofoils. Defining the flippers' shapes as triangular, swept pointed or swept rounded, the team used computer simulations of the fluid flows around the flippers and found that sweptback flippers generate lift like modern delta wing aircraft. Calculating the flippers' efficiencies, the team found that the bottle nose dolphin's triangular flippers are the most efficient while the harbour porpoise and Atlantic white-sided dolphin's fins were the least efficient.
Commenting that environmental and performance factors probably play a significant role in the evolution of dolphin and whale flipper shapes and their hydrodynamics, Howle and his colleagues are keen to find out more about the link between the flippers' performances and the environment that whales and dolphins negotiate on a daily basis.
Note: This story has been adapted from a news release issued by the The Company of Biologists
Post Comments:
| 
Subscribe
Ancient DNA from rare fossil reveals that polar bears evolved recently and adapted quickly
'Anaconda' meets 'Jurassic Park': Study shows ancient snakes ate dinosaur babies
Scientists locate apparent hydrothermal vents off Antarctica
Mars Express heading for closest flyby of Phobos
Artificial bee silk a big step closer to reality
Predicting the fate of stem cells
Artificial foot recycles energy for easier walking
New fiber nanogenerators could lead to electric clothing
What drives our genes? Researchers map the first complete human epigenome
Juggling enhances connections in the brain
Tracking down the human 'odorprint'
Fill 'er up - with algae
Scientists discover quantum fingerprints of chaos
Researchers help identify cows that gain more while eating less
American pika are thriving in the Sierra Nevada and southwestern Great Basin
Decoding the long calls of the orangutan
Barnacles prefer upwelling currents, enriching food chains in the Galapagos
Bringing bison back to North American landscapes
If bonobo Kanzi can point as humans do, what other similarities can rearing reveal?
Pesticide atrazine can turn male frogs into females
How can accidental captures of loggerhead turtles be reduced?
A convincing mimic: Scientists report octopus imitating flounder in the Atlantic
Study shows natural antioxidants give top barn swallows a leg on competitors
Fish can recognize a face based on UV pattern alone
New clues found linking larger animals to colder climates
The bigger the animal, the stiffer the 'shoes'
A magnetometer in the upper beak of birds?