The formation of sand ripples in a turbulent flow.

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Erick Franklin, Jorge Eduar Cardona Florez

Tuesday 30 june 2015

17:48 - 17:51h at Oceania (level 0)

Themes: (T) Sediment management and morphodynamics, (ST) River morphodynamics, Poster pitches

Parallel session: Poster pitches: 7B. Sediment - River

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The transport of grains by a fluid flow is frequently found in both nature and industry. Some examples are the transport of sand in rivers and channels, the transport of sand by wind, and the transport of sand in petroleum pipelines. When the shear stresses exerted by the fluid flow are moderate, some grains are set in motion without fluidizing the bed. The moving grains form a granular layer that moves while maintaining contact with the fixed part of the bed. In some cases, the granular bed becomes unstable, generating ripples and dunes. This paper presents an experimental study on the formation and migration of ripples under a turbulent liquid flow. In our experiments, fully-developed turbulent water flows were imposed over a granular bed of known granulometry. For different flow rates, the growth and migration of bedforms were filmed by a high-definition camera. The wavelength and the celerity of bedforms were determined from the acquired images.