Regensburg 2010 – wissenschaftliches Programm

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DY: Fachverband Dynamik und Statistische Physik

DY 30: Posters II

DY 30.47: Poster

Donnerstag, 25. März 2010, 16:00–18:00, Poster C

Diffusive and subdiffusive axial transport of granular material in rotating mixers — •David Fischer¹, Tilo Finger¹, Frank Angenstein², and Ralf Stannarius¹ — ¹Otto-von-Guericke-University Magdeburg — ²Leibniz Institute for Neurobiology Magdeburg

Binary granular mixtures tend to segregate by size when tumbled in a partially filled, horizontally rotating drum. After a few drum revolutions, the smaller component sinks below the flowing granular surface, forming a submersed radial core. After several dozen revolutions of the drum, the core can split into axial bands. Abnormal diffusion of the grains has been proposed to play an important role in that process [1]. On the other hand, DEM simulations indicate a normal Fickian diffusion in this system [2]. We measure axial diffusion of grains in binary mixtures, completely embedded in water, by means of Nuclear Magnetic Resonance Imaging (MRI). It is found that a narrow pulse of small size particles in a bed of large particles undergoes normal (Fickian) axial diffusion, whereas an initial narrow pulse of large particles in a bed of small particles shows subdiffusive behaviour [3].

[1] Z.S. Khan and S.W. Morris, PRL 94, 048002 (2005)

[2] N. Taberlet and P. Richard, PRE 73, 041301 (2006)

[3] in press PRE