title: Cooling and aggregation in wet granulates.
abstract: Wet granular materials are characterized by a defined bond energy in their particle interaction such that breaking a bond implies an irreversible loss of a fixed amount of energy. Associated with the bond energy is a nonequilibrium transition, setting in as the granular temperature falls below the bond energy. The subsequent aggregation of particles into clusters is shown to be a self-similar growth process with a cluster size distribution that obeys scaling. In the early phase of aggregation the clusters are fractals with D{f}=2, for later times we observe gelation. We use simple scaling arguments to derive the temperature decay in the early and late stages of cooling and verify our results with event-driven simulations.
authors.affiliation: Universität Göttingen, Institute of Theoretical Physics, 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: 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
authors.forename: Annette
authors.initials: A
authors.lastname: Zippelius