Communications of the ACM
Johns Hopkins Expert Finds Randomness Rules in Turbulent Flows
Johns Hopkins University professor Gregory Eyink has determined through computer experiments that turbulent fluid flows are dominated by randomness, and has confirmed earlier theoretical predictions that two identical beads dropped into the same turbulent flow at precisely the same starting point will end up in random destinations.
Eyink performed his study using a virtual stream that is part of an online public database of turbulent flow, and into this stream were dropped virtual particles at exactly the same point. Eyink then kicked each particle at random, and the particles followed different pathways when subjected to different kicks. However, Eyink observed that the particles still followed random, divergent paths even as the kicks got progressively weaker, suggesting that particles would follow different paths even without the kicks.
Eyink's experiments also verified that the magnetic lines of force that are carried along in a moving magnetized fluid move in an entirely random manner when the fluid flow is turbulent. This operates against the basic precept of magnetic flux-freezing, which dictates that magnetic lines of force are carried along in a moving fluid like strands of thread dropped into a flow.
From JHU Gazette
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