Berlin 2008 – scientific programme

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DY: Fachverband Dynamik und Statistische Physik

DY 29: Poster II

DY 29.50: Poster

Thursday, February 28, 2008, 16:00–18:00, Poster C

Dynamic behaviour of granular matter in a circular vibrated conveyor — •Michael Heckel, Christof A. Kruelle, and Ingo Rehberg — Universität Bayreuth, 95447 Bayreuth, Germany

Understanding the behaviour of vibrated granular matter is important because many industrial processes rely on mixed multicomponent substances. The system has to be driven with energy to stay in motion due to dissipative particle interactions. In studies this is mostly achieved by horizontal or vertical stimulation.

A horizontal and vertical oscillation with the same amplitude was superposed at a phase shift of π/2. In this way a circular oscillation for each point of the annular container is achieved. As granulate a binary mixture of black glass beads with a diameter of 1 mm and white glass beads with a diameter of 4 mm are used.

Above a threshold frequency of the excitation the bigger particles move to the top of the granulate which is known as the Brazilnut 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. By increasing the shaker frequency even further, a final state can be achieved where both particle species are completely separated in two distinct domains.