SEDIMENT TRANSPORT OVER RIPPLES IN WAVES AND CURRENT

G. Perrier, E.A. Hansen, C. Villaret, R. Deigaard, J. Fredsoe

Abstract


Numerical simulations are presented for the flow and the dynamics of noncohesive sediment over 2D ripples in waves and current. For this purpose, a model based on a discrete vortex approach using the "cloud-in-cell" concept has been applied. The hydrodynamic model drives a Lagrangian model for the suspended sediment. The characteristic vorticity structures prevailing in the vicinity of ripples are accurately replicated and sediment suspension mechanisms are successfully described. Thus, the sediment transport resulting from asymmetrical waves and combined waves and current can be predicted. Especially, the wave-related component of the transport opposes the maximum free stream velocity and contributes significantly to the total transport. In the present work, the effect of the wave-induced drift is not included.

Keywords


ripples; sediment transport; current

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