title: Dilute wet granular particles: nonequilibrium dynamics and structure formation.
abstract: We investigate a gas of wet granular particles covered by a thin liquid film. The dynamic evolution is governed by two-particle interactions, which are mainly due to interfacial forces in contrast to dry granular gases. When two wet grains collide, a capillary bridge is formed and stays intact up to a certain distance of withdrawal when the bridge ruptures, dissipating a fixed amount of energy. A freely cooling system is shown to undergo a nonequilibrium dynamic phase transition from a state with mainly single particles and fast cooling to a state with growing aggregates such that bridge rupture becomes a rare event and cooling is slow. In the early stage of cluster growth, aggregation is a self-similar process with a fractal dimension of the aggregates approximately equal to Df approximately 2 . At later times, a percolating cluster is observed which ultimately absorbs all the particles. The final cluster is compact on large length scales, but fractal with Df approximately 2 on small length scales.
authors.affiliation: Institute of Theoretical Physics, Universität Göttingen, 37077 Göttingen, Germany. ulrich@theorie.physik.uni-goettingen.de
authors.forename: Stephan
authors.initials: S
authors.lastname: Ulrich
authors.forename: Timo
authors.initials: T
authors.lastname: Aspelmeier
authors.forename: Annette
authors.initials: A
authors.lastname: Zippelius
authors.forename: Klaus
authors.initials: K
authors.lastname: Roeller
authors.forename: Axel
authors.initials: A
authors.lastname: Fingerle
authors.forename: Stephan
authors.initials: S
authors.lastname: Herminghaus