Business of Weather, The

HURRICANES

GREED IS GOOD," said the fictional stock market tycoon Gordon Gekko in the 1987 film "Wall Street." He was, of course, referring to tough takeover tactics employed by large, rapacious corporations against smaller rivals. But what works for Wall Street also apparently works in nature, when it comes to massive fluid vortices, like hurricanes and whirlpools. New research conducted at Johns Hopkins University and Los Alamos National Laboratory indicates that the hostile takeover business model may explain how large vortices acquire the energy to sustain themselves. An earlier theory suggested a more collegial business model: the merger. It was thought that big and small vortices mutually combined their assets. But the Johns Hopkins study concluded that large vortices act more like corporate raiders. They take over smaller eddies, suck the energy from them, then toss them aside to either die or renew themselves at the expense of even smaller vortices. The phenomenon is called a "reverse energy cascade." The two- and-a-half-year study focused on turbulent, two-dimensional flows of gas or liquid, like hurricanes and typhoons. Shiyi Chen, a professor of mechanical engineering at Johns Hopkins, says learning how hurricanes and large ocean eddies form is important. "It should help us to create better computer models to make more accurate predictions about these conditions." And as any Wall Street wheeler-dealer can tell you, predicting the future is never easy. -TG

Copyright American Society for Engineering Education Summer 2006
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