O Instituto Oceanográfico Woods Hole divulgou os resultados de uma pesquisa de Philip L. Richardson, cientista emérito da renomada instituição, que procurou desvendar os segredos da fantástia eficiência do voo do albatroz, que é capaz de voar distâncias enormes sem gastar quase energia.
Para isso, a ave usa o seu instinto para se beneficiar do efeito do vento sobre as ondas e até mesmo sobre veleiros, navios, etc.
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How Albatrosses fly such vast distances - tacking upwind
Woods Hole Oceanographic Institution discovers Albatrosses tack upwind
The answer, says Philip L. Richardson of the Woods Hole Oceanographic Institution (WHOI), lies in a concept called dynamic soaring, in which the large bird utilizes the power of above-ocean wind shear while tacking like an airborne sailboat.
An oceanographer may be offering the best explanation yet of one of the great mysteries of flight—how albatrosses fly such vast distances, even around the world, almost without flapping their wings.
'I have a simple model that explains the basic physics of what albatrosses do,' says Richardson, a scientist emeritus at WHOI, who, in addition to his primary career in studying ocean currents, has also piloted gliders. The key, he says, is the bird’s ability to balance the kinetic energy gained in soaring with the energy lost from drag.
As an albatross climbs from a wave trough, it is met by progressively faster winds that provide a burst of energy, increasing its speed significantly and carrying it as high as 10 to 15 meters.
Richardson was particularly intrigued by how the birds could be doing this while flying into the wind, something he had observed from a ship in the South Atlantic Ocean. 'It’s been a mystery how they fly this way,' he said.
It also explained the bird’s ability to seemingly fly upwind. To travel upwind, a sailor tacks into the wind. Richardson realized that albatrosses do the same thing. Using his model, he calculated that the bird tacks at about a 30-degree angle, 'like a sailboat.' 'They are using wind shear both ways,' he says. 'To climb up and dive down.' Using the model, he estimates that it takes a minimum wind speed of about seven knots for an albatross to soar.
In further describing this dynamic soaring, Richardson says what he has done is to refine previous models. While calculating that dynamic soaring accounts for the vast majority of energy for albatross flight, he says the remaining 10 to 20 percent comes from updrafts. 'It’s a simple model that explains what albatrosses do,' he said. 'It helps us understand how nature works.'
Beyond that, Richardson suggests that understanding albatross flight might help increase the speeds of radio-controlled gliders, or someday enable fleets of such gliders to be dispatched to measure oceans, he said.
The Woods Hole Oceanographic Institution is a private, independent organization in Falmouth, Mass., dedicated to marine research, engineering, and higher education. Established in 1930 on a recommendation from the National Academy of Sciences, its primary mission is to understand the ocean and its interaction with the Earth as a whole, and to communicate a basic understanding of the ocean's role in the changing global environment.
Instituto Oceanográfico Woods Hole.
Fonte: Sail World
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