title: Collective motion of macroscopic spheres floating on capillary ripples: dynamic heterogeneity and dynamic criticality.
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.
authors.affiliation: CompleXity 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.
authors.forename: Ceyda
authors.initials: C
authors.lastname: Sanlı
authors.affiliation: Multi Scale Mechanics, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands.
authors.forename: Kuniyasu
authors.initials: K
authors.lastname: Saitoh
authors.affiliation: Multi Scale Mechanics, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands.
authors.forename: Stefan
authors.initials: S
authors.lastname: Luding
authors.affiliation: Physics of Fluids, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands.
authors.forename: Devaraj
authors.initials: D
authors.lastname: van der Meer
mesh_terms: D005898:Glass; D009038:Motion; D017711:Nonlinear Dynamics; D013499:Surface Properties; D014867:Water
chemical_list: D014867:Water