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DY: Fachverband Dynamik und Statistische Physik

DY 30: Poster II

DY 30.57: Poster

Donnerstag, 29. März 2007, 16:00–18:00, Poster D

Coarsening of segregation patterns in a continuously rotating drum — •Tilo Finger and Ralf Stannarius — Otto-von-Guericke-Universität Magdeburg

The radial and axial segregation of granular mixtures in a long horizontal rotating drum has become one of the standard problems in the investigation of the physics of granular matter. Nevertheless the phenomena are incompletely understood so far. We investigate experimentally the structural properties and long term dynamics of the axial stripe pattern in a cylindrical drum which is initially half filled with a mixture of glass beads of different sizes and filled up with a liquid. The standard system is embedded in water. Rotation rates are chosen at low Froude numbers (Fr≪1). After starting a constant rotation rate a regular stripe pattern along the cylinder axis appears on the time scale of a few minutes. On a time scale of hours or days, the pattern coarsens by spontaneous dissolving of individual stripes. This was studied by optical and NMR methods [1]. We investigate the influence of viscosity and density of the interstitial fluid on the coarsening process. The relation between the level of segregation and the energy dissipation in the driving process is recorded and analyzed.

[1] T. Finger et al., Phys. Rev. E 74, 031312 (2006)