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DY: Fachverband Dynamik und Statistische Physik

DY 21: Granular Matter/Contact Dynamics

DY 21.6: Vortrag

Mittwoch, 28. März 2012, 15:45–16:00, MA 144

A two-species continuum model of aeolian sand transport — •Marc Lämmel, Daniel Rings, and Klaus Kroy — Institut für Theoretische Physik, Leipzig, Germany

Wind-driven sand transport is the dominant process shaping the geomorphology of arid regions on Earth, Mars and elsewhere. It is responsible for the spontaneous creation of a whole hierarchy of self-organized dynamic structures from ripples over isolated dunes to devastating fields of shifting sands. Provided that the wind is strong enough, you can even experience this transport process—called saltation—just by taking a walk on the beach, where sand clouds pass by, and every single grain tickles your ankles.

Here, we present a mathematical description of aeolian sand transport based on the successful continuum saltation model introduced in Ref. [1]. We show that a systematically improved version of this model can be derived by considering two species of trajectories, low-energy reptating grains and high-energy saltating grains—similar to what has been proposed in Ref. [2]. The resulting predictions are in remarkable agreement with flux data from various wind tunnel measurements.

• [1] Sauermann, G., Kroy, K., Herrmann, H.J., 2001. Continuum saltation model for sand dunes. Phys. Rev. E 64, 031305.
• [2] Andreotti, B., 2004. A two-species model of aeolian sand transport. Journal of Fluid Mechanics 510, 4770.