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arXiv · 0906.2167

Dilute Wet Granulates: Nonequilibrium Dynamics and Structure Formation

Stephan Ulrich·Timo Aspelmeier·Annette Zippelius·Klaus Roeller·Axel Fingerle·Stephan Herminghaus
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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 nonequillibrium 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 D_f ~ 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 D_f ~ 2 on small length scales.

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Stephan Ulrich, Timo Aspelmeier, Annette Zippelius, Klaus Roeller, Axel Fingerle, Stephan Herminghaus. 2009-06-11. Dilute Wet Granulates: Nonequilibrium Dynamics and Structure Formation. https://doi.org/10.1103/physreve.80.031306

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