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DY: Fachverband Dynamik und Statistische Physik

DY 62: Poster - Dynamics

DY 62.13: Poster

Donnerstag, 19. März 2015, 16:00–18:00, Poster A

Mesoscale Modelling of Aeolian Sand Transport — •Anne Meiwald, Marc Lämmel, and Klaus Kroy — Institute of Theoretical Physics, Leipzig, Germany

When driven by wind, sand in the desert or at the beach generates an impressive zoo of structures ranging from delicate ripples to wavy sand seas spanning orders of magnitude in their size. To understand how these structures emerge, it is essential to thoroughly describe of the underlying, seemingly chaotic, hopping motion of the sand grains. In order to make the complex grain scale physics more amenable to analytical studies, a coarse-graining approach was proposed that maps the ensemble of grain trajectories onto two populations representing fast salting and slow reptating grains [1,2]. On this basis, we now analyse the mesoscale structure of aeolian sand transport. We find the predicted mesoscopic observables like the mean hop length or height and particle velocity to be in a remarkable agreement with experimental data gained from various field and wind tunnel experiments. Since the physics on the mesoscopic scale is apparently insensitive to a higher resolution of the grains movement, we argue that our coarse-grained model offers a suitable starting point for the efficient numerical mesoscale modelling of aeolian sand transport and structure formation.

[1] Andreotti, B., J. Fluid Mech. 510, 47-70 (2004)

[2] Lämmel, M., Rings, D., Kroy, K., NJP 14, 093037 (2012)