Related papers: When barchan dunes move over craters
We apply a model for sand dunes to calculate formation of dunes on Mars under the present Martian atmospheric conditions. We find that different dune shapes as those imaged by Mars Global Surveyor could have been formed by the action of…
The collision processes of two crescentic dunes called barchans are systematically studied using a simple computer simulation model. The simulated processes, coalescence, ejection and reorganization, qualitatively correspond to those…
Almost fifty years of investigations of barchan dunes morphology and dynamics is reviewed, with emphasis on the physical understanding of these objects. The characteristics measured on the field (shape, size, velocity) and the physical…
Barchans are isolated mobile dunes often organized in large dune fields. Dune fields seem to present a characteristic dune size and spacing, which suggests a cooperative behavior based on dune interaction. In Duran et al. (2009), we propose…
The dune skeleton model is a reduced model to describe the formation process and dynamics of characteristic types of dunes emerging under unidirectional steady wind. Using this model, we study the dependency of the morphodynamics of…
The simplest type of dune is the transverse one, which propagates with invariant profile orthogonally to a fixed wind direction. Here we show numerically and with a linear stability analysis that transverse dunes are unstable with respect…
The dependence of the barchan dune dynamics on the size of the grains involved is investigated experimentally. Downsized barchan dune slices are observed in a narrow water flow tube. The relaxation time from an initial symmetric triangular…
Sand dunes are ubiquitous in nature, and are found in abundance on Earth and other planetary environments. One of the most common types are crescent-shaped dunes known as barchans, whose mid-line could be assumed to behave as 2D dunes. In…
Sand-moving winds blowing from a constant direction in an area of high sand availability form transverse dunes, which have a fixed profile in the direction orthogonal to the wind. Here we show, by means of a linear stability analysis, that…
Barchans are crescent-shaped sand dunes forming in aride regions with unidirectional wind and limited sand supply. We report analytical and numerical results for dune shapes under different environmental conditions as obtained from the…
Barchan dunes --- crescent-shaped dunes that form in areas of unidirectional winds and low sand availability --- commonly display an asymmetric shape, with one limb extended downwind. Several factors have been identified as potential causes…
We apply a mean-field model of interactions between migrating barchan dunes, the CAFE model, which includes spontaneous calving, aggregation, fragmentation, and mass-exchange, yielding a steady-state size distribution that can be resolved…
To analyze theoretically the stability of the shape and the migration process of transverse dunes and barchans, we propose a {\it skeleton model} of 3D dunes described with coupled dynamics of 2D cross-sections. First, 2D cross-sections of…
Barchan dunes were found to transform into parabolic dunes and vice versa when the amount of vegetation on and around them changes. This work presents the first numerical simulation of this effect. We propose a continuum model for the…
This paper reports a downscaled water tunnel experiment to study the temporal characteristics of a double dune interaction system and the new pattern of dune interaction when the initial mass ratio of the two dunes is large. These topics…
Barchan dunes are found where sand availability is low and wind direction quite constant. The two dimensional shear stress of the wind field and the sand movement by saltation and avalanches over a barchan dune are simulated. The resulting…
In a recent experimental breakthrough, Hersen et al. [1] demonstrated that by changing the agitating medium from air to water, one can obtain, on laboratory scale, dunes that are downsized copies of desert dunes, thereby overcoming a major…
We reply to the comment by Andreotti and Claudin (submitted to Phys. Rev. E, arXiv:0705.3525) on our paper ``Minimal Size of a Barchan Dune'' [Phys. Rev. E {\bf{75,}} 011301 (2007)]. We show that the equations of the dune model used in our…
The observed temporary dark streaks on some dune slopes on Mars may be due to thin sheets of water (or some other liquid) trickling downhill. This note corrects conceptual errors in a previous paper (M\"{o}hlmann and Kereszturi 2010, Icarus…
Barchan dunes emerge as a collective phenomena involving the generation of thousands of them in so called barchan dune fields. By measuring the size and position of dunes in Moroccan barchan dune fields, we find that these dunes tend to…