8th Liquid Matter Conference September 6-10, 2011 Wien, Austria ...

Tue 611:23-14:00P9.71Dynamics of the 2D airbed granular systemChen-Hung Wang 1 and Peilong Chen 11 Department of Physics and Center for Complex Systems, National Central University,No. 300, Jhongda Rd., 32001, Jhongli, TaiwanWe build a 2D granular system with disc-like granules levitated by airflow on the top of a plate. Theairflow, injected through pinholes in the plate, also provides granules an additional lateral randomagitation that can be controlled by changing the flow rate. The dynamics of the system is slower andthe mutual interactions are more controllable than the other air-driven ones. Permanent cylindricalmagnets are embedded in a granule with different strength, and orientations (dipole directionsperpendicular or parallel to the plate) to induce repulsive, attractive, or even chiral interactions.With simple dipolar repulsion, melting dynamics from crystal cage motion to ”liquid-like” hoppingare observed. The orientational order and velocity correlations through the melting of this granularcrystal are compared to the two-stage melting of the 2D colloid crystal. Besides single granule,we also connect granules with rotation-free junctions to form a long granular chain. Comparisonsbetween the motions of this long granular chain in a bath of regular granules and the dynamics ofa single macromolecule are also made.71