Regensburg 2010 – scientific programme
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DY: Fachverband Dynamik und Statistische Physik
DY 9: Granular Matter/ Contact Dynamics I
DY 9.8: Talk
Tuesday, March 23, 2010, 11:45–12:00, H47
Self-assembled granular walkers — •Zeina Khan1, Audrey Steinberger2, Ralf Seemann1,3, and Stephan Herminghaus1 — 1Max Planck Institute for Dynamics and Self-Organization, Göttingen, Germany — 2Laboratoire de Physique, Ecole Normale Supérieure de Lyon, Lyon, France — 3Experimental Physics, Saarland University, Saarbrücken, Germany
We have observed that when a bi-disperse mixture of glass beads is moistened by a fluid and shaken sinusoidally in a vertical container, small clusters of beads take off from the surface of the pile and rapidly climb up the container walls against gravity. These self-organized clusters are held together and against the wall by liquid capillary bridges, and are led by one large grain with one or more small grains trailing behind. When similar clusters are placed on a horizontally vibrating substrate they self-align and travel horizontally along the axis of vibration with a ratchet-like motion. We report on properties of this novel system, such as the clusters’ speed as a function of the asymmetry of the structure and the driving acceleration. We also present a model that accounts for the observed behavior.