speed of dolphins figured out

November 26th, 2008

 

The team tracked the bubbles around a dolphin. The more prominent the colour, the faster the water is moving.

New research has shown how dolphins achieve their blinding speeds.

Gray’s Paradox – named after British zoologist Sir James Gray – proposed that dolphins simply do not have the strength to swim so fast.

But researchers at the Rensselaer Polytechnic Institute in the US have now studied the movement of water around dolphins as they swim.

The results show that dolphins can exert as much as 180kg (400lb) of force with their tails.

Gray had supposed they could produce less than a tenth of this amount, and imagined that something about the dolphins’ skin allowed them to overcome the force of drag in the water and reach high speeds.

“For the first time, I think we can safely say the puzzle is solved,” said Tim Wei, the Rensselaer scientist who led the study.

“The short answer is that dolphins are simply much stronger than Gray or many other people ever imagined.”

To determine this, Professor Wei used a new method of measuring the movement of water that he originally developed to track Olympic swimmers.

Dolphin and Cilla (BBC)

Keeping upright for Cilla Black requires a lot more force

The technique employs digital particle image velocimetry, which measures the speed of water movements around a swimming dolphin or human.

Retired US Navy dolphins Primo and Puka were filmed swimming through a tank filled with millions of tiny bubbles.

Software tracked the movement of individual bubbles, determining their speed and direction, and assigning them a colour.

Professor Wei then used force measurement concepts from aerospace research to translate those velocities into a force that the dolphins’ tails were producing – nearly 100kg (200lb) on average.

When “walking” – keeping upright mostly above water with powerful flips of their tails – the dolphins produced as much as 180kg of force.

Professor Wei will go on to study the motion and force generation of other sea animals

 

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    Stuffed into an 8 pound flesh covered space suit in Southern California in 1944, Barbara Ann Moore was born at a very early age. Her uneventful childhood, with a yarn-spinning Alabama father and Virginia Virgo mother, two humorous older brothers and a singing beagle, was full of love and laughter. As a professional student with no particular profession in mind, Barbara attended several colleges and universities on the undergraduate as well as the graduate level. Briefly married (also at an early age), Barbara worked as a lab tech in the hospital before she became an academic adviser at Iowa State University and later, in California, at the State University at Chico. Her life took a distinct 180 turn in the '70's when she met a colorful psychedelic artist who wanted to “score” a chick and move to Hawaii. Since her multiple Scorpio phoenix bird reincarnations in Hawaii, Barbara has primarily been crafting the Healing Arts Center (see About Us on www.dragonflyranch.com) called the Dragonfly Ranch--begun in 1974. Along the way, Barbara studied with a number of respected kahunas who taught her Hawaiian lomilomi (a sacred rejuvenation treatment), ho’oponopono (a method of "setting things right") and Hawaiian healing herbs. With the help of quality assistance from her Ohana (adopted family), three dogs and one cat, Barbara hosts discerning travelers looking for an authentic Hawaiian experience, enjoying Healthy Pleasures. Elected president of Hawaii Island Wellness Travel Association (HIWTA.org), Barbara is learning how to interview members for youTube "webasodes". Besides loving her life at the Dragonfly, Barbara’s present personal passion is to finish her screenplay called, “To Die Laughing”, a romantic comedy about death.
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