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DY: Fachverband Dynamik und Statistische Physik

DY 40: Posters II

DY 40.21: Poster

Thursday, March 17, 2011, 17:00–19:00, P3

The “Minimal Model 2.0”: An accurate and efficient continuum description of sand dune formation — •Marc Lämmel, Daniel Rings, and Klaus Kroy — Institut für Theoretische Physik, Universität Leipzig, Germany

The so-called “minimal model” [1] is a continuum model of aeolian sand transport that can explain the formation and migration of sand dunes in the desert. What makes it conceptually and practically very appealing is that it captures the essential physical mechanisms while being computationally simple. Yet, recent research has demonstrated certain shortcomings of this popular model. Comparing the predicted dependence of the saturated sand flux on the wind speed with wind tunnel observations reveals a systematic deviation of that quantity: For stronger winds the model overestimates the flux significantly.

Here we show that a systematically improved version of the minimal model can be derived by considering two species of trajectories, similar to what has been proposed in Ref. [2]: low-energy reptating grains and high-energy saltating grains. The resulting predictions are in remarkable agreement with flux data from various wind tunnel measurements.

[1] G. Sauermann, K. Kroy, and H. J. Herrmann (2001, Aug). Continuum saltation model for sand dunes. Phys. Rev. E 64 (3), 031305.

[2] B. Andreotti (2004). A two-species model of aeolian sand transport. Journal of Fluid Mechanics 510, 4770.