Dresden 2009 – wissenschaftliches Programm

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DY: Fachverband Dynamik und Statistische Physik

DY 28: Pattern formation in colloidal and granular systems II

DY 28.10: Vortrag

Freitag, 27. März 2009, 12:45–13:00, HÜL 386

Unstable Kolmogorov flow in granular matter — •Klaus Roeller and Stephan Herminghaus — MPI for Dynamics and Self-Organization, Bunsenstr. 10, D-37073 Göttingen, Germany

We report on simulations of an instability in granular flow, which is driven by a time-constant spatially periodic shear force. This type of forcing is known as Kolmogorov flow. We performed molecular dynamics type simulations, both time-driven and event-driven, in two and three dimensions [1,2]. For small values of the applied shear force we observe the usual shear bands. Above a critical value, however, the shear bands become unstable resulting in the formation of a dynamically stable pattern with swirls. This effect was observed in dry as well as in wet granular matter, although the morphology of the swirls strongly differs for the two cases.

[1] S. Herminghaus Advances in Physics 54, 221 (2005)

[2] A. Fingerle, et al, New J. Phys. 10, 053020 (2008)