Erosion waves: Transverse instabilities and fingeringF. Malloggi, J. Lanuza, B. Andreotti and E. Clément
Laboratoire de Physique et Mécanique des Milieux Hétérogènes, UMR CNRS 7636 Univ. P6&P7 - 10, rue Vauquelin, 75005 Paris, France
received 6 March 2006; accepted in final form 13 July 2006
published online 28 July 2006
Two laboratory scale experiments of dry and underwater avalanches of non-cohesive granular materials are investigated. We trigger solitary waves and study the conditions under which the front is transversally stable. We show the existence of a linear instability followed by a coarsening dynamics and finally the onset of a fingering pattern. Due to the different operating conditions, both experiments strongly differ by the spatial and time scales involved. Nevertheless, the quantitative agreement between the stability diagram, the wavelengths selected and the avalanche morphology suggest a common scenario for an erosion/deposition process.
83.50.Lh - Slip boundary effects (interfacial and free surface flows).
92.40.Gc - Erosion and sedimentation; sediment transport.
83.80.Fg - Granular solids.
© EDP Sciences 2006