11:00 am Wednesday, May 3, 2006
Mathematical Physics Seminar (Joint with ICES): Velocity Statistics for Non-Equilibrium Steady-States in 2D Granular Fluids by Mark Shattuck (City University of New York) in RLM 12.166
We report on the experimental velocity statistics in 2D granular fluids for three different geometries: horizontal uniformly heated, vertical heated from below, and rotated. Each of these flows are steady-states, but progressively further out of equilibrium. However we find a universal velocity distribution which describes each case. In particular it captures the highest probability deviations from a Maxwell-Boltzmann. We use stainless steel spheres (diameter D), confined by two glass plates. In the uniformly heated case, the plates are horizontal and separated by 1.6 D with a rough bottom plate which effectively transfers momentum from the vertical shaking into the horizontal plane. This allows us to study a large range of filling fractions. In the vertically heated case, the plates are vertical and separated by 1.05 D with a weight on top and a vertically vibrating bottom. In the rotating case, the wall are vertical with a separation of 1.6D and rotated about the horizontal. We compare and contrast the single particle velocity distributions in the various geometries and with standard kinetic theory assumptions. Submitted by
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