Regensburg 2002 – wissenschaftliches Programm

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DY: Dynamik und Statistische Physik

DY 53: Granulare Materie

DY 53.4: Vortrag

Freitag, 15. März 2002, 12:15–12:30, H3

Segregation in granular matter under horizontal swirling excitation — •Sebastien Aumaitre¹, Christof Krülle², and Ingo Rehberg² — ¹LPS-ENS, F–75231 Paris — ²Experimentalphysik V, Universität Bayreuth, D–95440 Bayreuth

We will present some experimental results about the segregation phenomena in a monolayer of a binary mixture shaken by a horizontal swirling in a circular cell. Two different cases have been investigated. In the first case, the two different species of particles, i.e., small spheres which roll and large disks which only slide, have very different mobility under the horizontal swirling excitation. In the second case, a binary mixture of small and large spheres, all particles roll with almost the same velocity. These two cases lead to two different mechanisms for segregation. In the first case, segregation seems essentially due to the mobility difference. The disks go always to the center of the cell, independently of the particle density. In the second case, the segregation of the large spheres occurs only at high density. The corresponding critical density where this size segregation starts appears to be the same as the critical density which we observe for the phase transition in a monodisperse layer under the same excitation conditions.