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JOURNAL OF GEOPHYSICAL RESEARCH,
VOL. 110,
F04S07,
10 PP., 2005
doi:10.1029/2004JF000185
Flow effects on the morphology and dynamics of aeolian and subaqueous barchan dunes
Laboratoire de Physique Statistique, Ecole Normale Supérieure, Paris, France
Physics Department, Danish Technical University, Lyngby, Denmark
Barchans are aeolian sand dunes that form where unidirectional winds blow on firm ground with limited sand supply. Although they have been analyzed for decades, the difficulty of conducting experiments in the field, due to the large lengthscale and timescale involved, is a considerable obstacle to understand their dynamics. However, crescentic patterns also appear underwater on a much smaller scale, allowing easier study. It is shown here that down-scaled solitary barchans can be created in the laboratory using the periodic and asymmetric motion of a plate underwater to simulate the effect of a unidirectional flow. Those subaqueous barchans compare very well to their aeolian relatives. Their speeds scale as the cube of the speed of the flow times the inverse of their typical dimension. Finally, the exploration of new topics, such as the influence of the directionality of the wind or that of binary collisions, illustrate that barchans can eventually adapt to any external perturbations by emitting one or several small barchans.
Received 15 June 2004; accepted 18 May 2005; published 16 November 2005.
Citation: (2005), Flow effects on the morphology and dynamics of aeolian and subaqueous barchan dunes, J. Geophys. Res., 110, F04S07, doi:10.1029/2004JF000185.
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