Dresden 2014 – wissenschaftliches Programm

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DY: Fachverband Dynamik und Statistische Physik

DY 18: Granular Matter / Contact Dynamics

DY 18.2: Vortrag

Mittwoch, 2. April 2014, 09:45–10:00, ZEU 118

Emergent surface tension in driven granular media. — •James PD Clewett — Max Planck Institute for Dynamics and Self-Organization, Am Faßberg 17, 37077 Göttingen, Germany

A liquid-gas-like phase separation is observed in vertically vibrated granular media confined between two horizontal plates. Experiments and simulations were used to show that the coarsening dynamics are spinodal in nature, similar to a system undergoing curvature driven diffusion in the presence of a surface tension (model B). By studying quasi-2d, circular droplets we find behaviour consistent with Laplace's equation. Measurements of the pressure tensor in the interfacial region show that the surface tension is mainly due to an unexpected anisotropy in the kinetic energy components. This is in contrast to equilibrium thermodynamic systems, where surface tension arises due to attractive interactions between particles, or entropic considerations.