Think of scenes from the movie "Twister." Tornado chasers load uptheir trucks with ping-pong-ball-sized spheres and head for a twister. Thespheres are then released into the storm's vortex, resulting in thetransmission of valuable scientific information on tornadoes' actions to thechasers' computers.
Life imitates art: Cornell researchers are releasing a myriad oftiny spheres, each about the size of a speck of dust, into flowing water. The information they get back explains how particles behave in a turbulent environment. This basic understanding of turbulence can tell researchers much about our everyday world, reported Greg A. Voth, a Cornell graduate student, at the centennial meeting of the American Physical Society in Atlanta. "Perhaps it can be used for weather modeling, understanding how air and fuel mix in a combustion engine or the spreading of pollution in the airor the ocean," he said.
The researchers look into the swirls and twists of turbulence by placing tiny polystyrene spheres, each about 50 microns across, into a water flow. As the particles cross a laser beam, the scientists can take as many as 70,000 images a second and measure speed and acceleration of the minuscule spheres.
To explain this tracking concept, Voth used the example of pointing a floodlight into a snowstorm on a dark night. "When you point the beam, you see the snowflakes go through their curved trajectories as they follow the wind," he said. By tracking millions of particles, the Cornell researchers are learning about the fundamental nature of turbulent flows, which could lead to practical uses such as understanding how pollution particulates cross the oceans or how fuel mixes with air inside an engine, resulting in the development of more fuel-efficient engines.
Voth's faculty adviser, Eberhard Bodenschatz, Cornell associate professor of physics, explains that the particles behave the same way, whether in air orwater, and the statistics and the dynamics are the same. Other collaborators on the project include Arthur LaPorta, Cornellpost-doctorate researcher, who also presented his findings on the researchat the meeting, and James Alexander, Cornell associate professor of physics.
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