Author(s): C. Berni; H. Michallet; E. Barthelemy
Linked Author(s):
Keywords: Bed destabilization; Pore pressure; Infiltration/exfiltration; Acceleration; Flume experiment
Abstract: Experiments on a beach were carried out in a wave flume. The beach is made of lightweight sediment to fulfil Shields and Rouse scaling in order to reproduce sediment destabilizing and erosion processes in a controlled environment. The repetition of identical wave sequences on an equilibrium beach profile allows reliable phase average measurements of velocity, bed and top sheet flow elevation, pressure and concentration near the bed. The relative importance of infiltration/exfiltration, acceleration, pressure gradients on the erosion is analysed. It appears that the sheet-flow is the thickest under the wave crests, indicating that the erosion is mainly driven by the cross-shore velocity outside the boundary layer. On the other hand we find a good correlation between the fluid accelerations and the time evolution of sheet-flow thickness. Finally, the exfiltration/infiltration is found to play a minor role in the sheet-flow dynamics.
Year: 2011