Berlin 2005 – wissenschaftliches Programm

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DY: Dynamik und Statistische Physik

DY 24: Granular Matter

DY 24.6: Vortrag

Samstag, 5. März 2005, 15:30–15:45, TU H2032

Collective Behavior in Size Segregation of Granular Materials — •Stephan Ulrich, Matthias Schröter, and Harry L. Swinney — CNLD, University of Texas at Austin

Shaking a bidisperse mixture of particles can cause the large ones to rise (Brazil-nut effect) or to sink (reverse Brazil-nut effect). Studies of size segregation are often done in the limit of a single large intruder. However, theories based on granular temperatures (e.g. [1]) require collective interplay of many particles. Using image analysis, we experimentally investigate the importance of collective effects. Therefore the fraction of large particles is changed from a single intruder to equal layer heights. Furthermore, the influence of the total layer height is examined. We find the reverse Brazil nut effect to be strongest in the single intruder limit, where segregation is not driven by collective effects like fluidization

[1] D. C. Hong, P. V. Quinn, and S. Luding, Phys. Rev. Lett. 86, 3423 (2001)