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DY: Fachverband Dynamik und Statistische Physik
DY 22: Granular Matter/ Contact Dynamics
DY 22.6: Talk
Wednesday, March 16, 2011, 15:15–15:30, HÜL 186
Spiral Patterns in Vertically Vibrated Wet Granular Matter — •Kai Huang and Ingo Rehberg — Experimentalphysik V, Universität Bayreuth, D-95440, Germany
Spiral patterns widely exist in nature and have been extensively studied in various non-equilibrium systems. As a peculiar example, we report here spiral patterns in a few layers of cohesive glass beads driven by vertical vibrations. The cohesion is introduced by adding few percent of wetting liquid into the sample so that the particles are bonded with each other by liquid bridges. As the vibration amplitude reaches a certain threshold, traveling waves or rotating spiral patterns start to appear. These spiral patterns have typically a meandering core and three rotating arms which are associated with the three phases of a parametrically driven oscillation with period 3. The phase diagram for the pattern forming system will be presented and the mechanism for the spiral patterns will be discussed.