Regensburg 2007 – scientific programme

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DY: Fachverband Dynamik und Statistische Physik

DY 31: Granular matter / contact dynamics II

DY 31.9: Talk

Friday, March 30, 2007, 12:15–12:30, H2

Lateral segregation of bidisperse mixtures — •Michael Heckel, Andreas Götzendorfer, Christof Krülle und Ingo Rehberg — Experimentalphysik V, Universität Bayreuth, D-95440 Bayreuth, Germany

The understanding of the behaviour of vibrated granular matter is important because many industrial processes rely on mixed multicomponent substances. In the last years 'granulodynamics', i.e. the physics of granular media, has attracted the interest of physicists as well. In our experiments we study a binary mixture of spheres with different sizes in a circular vibrated environment on an especially designed vibratory conveyor [1]. Above a threshold frequency of the excitation the bigger particles move to the top of the granulate similar to the Brazil-nut effect (BNE). If a second threshold frequency is exceeded another separation begins to dominate which can be seen as well-separated monodisperse domains in the vibrated bed. This reminds to phenomena known for purely horizontally shaken binary granular mixtures [2]. By increasing the shaker frequency even further a final state can be achieved where both particle species are separated completely in two distinct domains.

[1] M. Rouijaa, C. Krülle, I. Rehberg, R. Grochowski und P. Walzel, Transportverhalten und Strukturbildung granularer Materie auf Schwingförderern, Chemie Ingenieur Technik 76, 62 (2004)

[2] P.M. Reis and T. Mullin, Granular segregation as a critical phenomenon, Phys. Rev. Lett. 89, 244301 (2002)