Of colorful candies
and fluid dynamics
Posted April 16, 2013
Development of a rough diffusive interface between two miscible fluids in zero gravity. Click image to enlarge and for more information.
Students who wheeled a 55-gallon drum filled with M&Ms into a Princeton physicist’s office a decade ago unwittingly helped launch the career of mathematician Aleksandar Donev.
Donev uses computer simulations to study how thermal fluctuations affect fluid behavior at scales comparable to the size of molecules. “Gases and liquids behave very differently at the molecular level than at the scale of millimeters, centimeters, meters and kilometers,” says Donev, an assistant mathematics professor at New York University’s Courant Institute. “My research is finding out what this behavior is and why it is important.”
Prestigious fellowships at Lawrence Berkeley and Lawrence Livermore national laboratories and multiple honors – he’s finishing up the first year of five as a Department of Energy Early Career Research Award recipient – attest to the enthusiastic response to Donev’s work.
He’s a prolific communicator who started publishing as a Michigan State University physics undergraduate and has since authored and co-authored dozens of papers. Today, he uses computer animations to illustrate scientific concepts such as the random motion of discrete particles – atoms and molecules – that are the beating hearts of every fluid.
In “constant agitated thermal motion,” Donev says, these particles “move in seemingly random directions.” His animations depict tiny particles skittering across a fluid, illustrating Brownian motion. Reds, oranges, yellows, greens and blues burst across the screen as fluids mix in strong, weak and zero gravity. Light blues, dark blues and vibrant yellow animate the unfolding Rayleigh-Taylor instability, typically seen as oil mixes with water.