Berlin 2005 – wissenschaftliches Programm

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DY: Dynamik und Statistische Physik

DY 34: Poster

DY 34.95: Poster

Montag, 7. März 2005, 15:30–18:00, Poster TU D

Large Height fluctuations in a two-dimensional air fluidized bed — •Sabrina Nagel, Matthias Schröter, and Harry Swinney — Center for Nonlinear Dynamics, University of Texas at Austin

This work examines relaxation and compaction of a two dimensional granular system. It tests a proposed thermodynamic description of static granular media introduced by Edwards and co-workers. After being tapped with a pulse of air, the binary granular bed relaxes into a steady state volume about which the volume fluctuates as tapping goes on. The idea is to use the volume fluctuations to determine the compactivity X, which was introduced by Edwards and co-workers. For this purpose, a Gaussian is fitted to the histogram of deviations from the local average. The variance of the Gaussian is needed to calculate X. The steady state volume depends on the parameters of the tap, pulse duration and pulse strength. We found that the variance is a function of the steady state volume. This indicates that X is indeed a well-defined parameter.