Granular size segregation in underwater sand ripples
Physique et Mécanique des Milieux Hétérogénes (PMMH), UMR CNRS-ESPCI 7636, 10 rue Vauquelin, 75231, Paris Cedex 05, France
2 Group for Research and Applications in Statistical Physics (GRASP), Institut de Physique B5, Université de Liége, 4000, Liége, Belgium
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We report an experimental study of a binary sand bed under an oscillating water flow. The formation and evolution of ripples is observed. The appearance of a granular segregation is shown to strongly depend on the sand bed preparation. The initial wavelength of the mixture is measured. In the final steady state, a segregation in volume is observed instead of a segregation at the surface as reported before. The correlation between this phenomenon and the fluid flow is emphasised. Finally, different “exotic” patterns and their geophysical implications are presented.
© EDP Sciences, Società Italiana di Fisica, and Springer-Verlag, 2004