Regensburg 2007 – wissenschaftliches Programm

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DY: Fachverband Dynamik und Statistische Physik

DY 5: Fluid dynamics I

DY 5.1: Hauptvortrag

Montag, 26. März 2007, 14:00–14:30, H2

Dynamics of Dunes — •Hans Herrmann — ETH, Zürich, Switzerland

Dunes exist along coasts, in deserts and also on other planets like Mars. They are aerodynamic instabilities formed on free granular surfaces. By formulating a set of equations of motion for the height of the surface, the sand flow and the shear stress of the wind it is possible to describe the formation and evolution of dunes. Using adecuate boundary conditions one gets quantitative agreement with field measurements. Including a further equation for the growth of vegetation one can also calculate dune fixation and observe the transition between croissant-shaped "barchan" dunes and parabolic dunes. Inserting the parameters for Mars also the recently observed shapes of Mars dunes can be reproduced.