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Updated: Apr 22, 2026

An Analog Macroscopic Technique for Studying Molecular Hydrodynamic Processes in Dense Gases and Liquids
Published on: December 4, 2017
Collective motion of macroscopic spheres floating on capillary ripples: dynamic heterogeneity and dynamic criticality
Ceyda Sanlı1, Kuniyasu Saitoh2, Stefan Luding2
1CompleXity and Networks, naXys, University of Namur, 5000 Namur, Belgium and Physics of Fluids, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands.
Abstract:
When a densely packed monolayer of macroscopic spheres floats on chaotic capillary Faraday waves, a coexistence of large scale convective motion and caging dynamics typical for glassy systems is observed. We subtract the convective mean flow using a coarse graining (homogenization) method and reveal subdiffusion for the caging time scales followed by a diffusive regime at later times. We apply the methods developed to study dynamic heterogeneity and show that the typical time and length scales of the fluctuations due to rearrangements of observed particle groups significantly increase when the system approaches its largest experimentally accessible packing concentration. To connect the system to the dynamic criticality literature, we fit power laws to our results. The resultant critical exponents are consistent with those found in densely packed suspensions of colloids.
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