Dresden 2006 – wissenschaftliches Programm
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DY: Dynamik und Statistische Physik
DY 25: Granuar Matter and Contact Dynamics I
DY 25.4: Vortrag
Dienstag, 28. März 2006, 15:15–15:30, SCH 251
Axial segregation of granulate in a long horizontal rotating drum — •Tilo Finger1, Andreas Voigt2, and Ralf Stannarius1 — 1Otto-von-Guericke-University Magdeburg — 2Max-Planck-Institute for Dynamics of Complex Technical Systems Magdeburg
The axial segregation of granular material in a long horizontal rotating drum is a well known phenomenon. We investigate experimentally the structures and the long time behaviour of this process. The drum is half filled with a mixture of glass beads of two different diameters and filled up with water. After starting a constant rotation, the material shows a radial segregation on a time scale of few seconds. On a time scale of few minutes, an additional axial segregation appears and a stripe pattern along the cylinder axis becomes visible. The initial width of stripes is more or less regular. When the rotation continues, the number of stripes decreases. The time scale of coarsening of the pattern is of the order of several hours up to days. We measure the coarsening at different rotation frequencies and determine the three dimensional distribution of the grains by magnetic resonance imaging. By preparation of initial stripe patterns with well defined geometry, we analyse details of the coarsening process and the relation between the 3D segregation structures and coarsening dynamics.