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DY: Fachverband Dynamik und Statistische Physik

DY 29: Poster II

DY 29.52: Poster

Donnerstag, 28. Februar 2008, 16:00–18:00, Poster C

Mini-Ripples in fine granular matter — •Simon Fischer, Ingo Rehberg, and Christof Krülle — Experimentalphysik V, Universität Bayreuth, D-95440 Bayreuth

In 1940 R.A. Bagnold, one of the pioneers in the field of wind blown grains, discovered a small scale ripple structure in very fine sand in wind tunnel experiments. He described these ripples to have an - in comparison to known structures in coarse sand - extremely small wavelength, of about one centimetre near the threshold for grain motion. Moreover, he noticed an "interesting change in the ripple formation" towards "new ripples on a much larger scale" when the wind reached a certain critical strength [1]. Although many theories, simulations and experiments have been performed on wind driven ripple formation in coarse granular matter [2], science has not taken a closer look to structures in fine granular matter. In our setup we are able to investigate the formation, growth and long time behaviour of these mini-ripples to gain a better understanding of this phenomenon and its relation to other ripple structures observed in nature.

[1] R.A. Bagnold, The physics of blown sand and desert dunes (Chapman & Hall, London 1941)

[2] B. Andreotti, P. Claudin, O. Poliquen, Phys.Rev.Lett.. 96,028001 (2006)