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DY: Fachverband Dynamik und Statistische Physik

DY 24: Pattern formation in colloidal and granular systems I

DY 24.4: Talk

Thursday, March 26, 2009, 15:30–15:45, ZEU 255

Humidity determines granular transport hysteresis — •Tobias Lang¹, Christof Krülle^1,2, and Ingo Rehberg¹ — ¹Universtität Bayreuth, Universitätsstrasse 30, D-95447 Bayreuth — ²Maschinenbau und Mechatronik, Hochschule Karlsruhe - Technik und Wirtschaft, D-76133 Karlsruhe

Since the pioneering works of R.A Bagnold, a grown interest in dune dynamics evolved. Incipient motion of a sand bed starts, when the wind speed over the bed surpasses a critical threshold. It is known that the sand flux depends sensitively on the humidity of the air. Using a small scale closed-circuit wind tunnel with active moisture control, we studied the dependency of the granular transport process on the humidity. Via the variation of humidity, electrostatic charging of the particles can also be influenced. In particular we measure the hysteretic dependence of the sand flux on the wind speed.