Europhys. Lett.
Volume 69, Number 3, February 2005
Page(s) 365 - 370
Section Electromagnetism, optics, acoustics, heat transfer, classical mechanics, and fluid dynamics
Published online 24 December 2004
Europhys. Lett., 69 (3), pp. 365-370 (2005)
DOI: 10.1209/epl/i2004-10366-3

Non-aeolian sand ripples

J. F. Boudet, Y. Amarouchene, B. Bonnier and H. Kellay

CPMOH (UMR5798), U. Bordeaux 1 - 351 cours de la Libération 33405 Talence, France

received 1 September 2004; accepted in final form 24 November 2004
published online 24 December 2004

By examining the initial stages of the impact of a granular jet on a flat horizontal solid surface we evidenced the existence of oscillatory sand fronts. These oscillations give rise to a novel mechanism for the formation of ripples on sand surfaces. We here show that as the front advances, its slope changes periodically in time, leaving behind a succession of surface elevations and depressions. A key feature of these oscillations is the interplay between the deposition of mobile sand and the avalanching of the static parts giving rise to a remarkable self-regulating system. These features come out naturally from a simplified version of recently proposed models for the dynamics of sand piles.

45.70.-n - Granular systems.
45.70.Ht - Avalanches.
45.70.Qj - Pattern formation.

© EDP Sciences 2005