Dresden 2006 – wissenschaftliches Programm

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DY: Dynamik und Statistische Physik

DY 27: Granular Matter and Contact Dynamics II

DY 27.5: Vortrag

Dienstag, 28. März 2006, 17:30–17:45, SCH 251

Velocity distributions of levitated granular gases — •Corinna Maaß, Nathan Isert, Christof Aegerter, and Georg Maret — Fachbereich Physik, Universität Konstanz, Universitätstrasse 10; 78457 Konstanz

Granular gases can show counterintuitive behaviour, such as clustering, non-Maxwellian velocity distributions and de-mixing. Theoretical studies have emphasised the role of inhomogeneous heating, collisions with boundaries and gravity on these effects, as well as the possibility of observing Maxwell-Boltzmann distributions also in granular materials. This is mainly due to the inelasticity of the collisions and different restitution coefficients of the bounding walls. In order to study the influence of the above effects, we diamagnetically levitate granular gases of different constituting particles, such as polystyrene and bismuth. A homogeneous heating of the granular gas is achieved by adjusting the magnetic field gradient, such that there is a simultaneous forcing of all of the granular particles. The resulting velocity distributions are recorded using video-microscopy and particle tracking. We also discuss the influence of particle number and restitution coefficient on the dynamics of the granular gas.