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Accueil > Actualités > Séminaires > Séminaires 2021

Mardi 6 Juillet 11h00 - LEGI Salle K118

Ali Salimi-Tarazouj, Center for Applied Coastal Research (CACR), University of Delaware

Titre/Title : A Eulerian Two-Phase Modeling of Sand Ripple Dynamics under Oscillatory Flow

Contact : Julien Chauchat (équipe MEIGE)

Résumé/Abstract : Seabed sand ripples with a variety of lengths and heights are ubiquitous in the sandy near-shore regions. The complex coupling between flow and sediment transport determines the ripple geometry which affects the energy dissipation of waves and currents, post-storm beach recovery, acoustic sensor operation, and benthic ecosystems. Although many equilibrium-ripple geometry predictors have been developed, there are significant discrepancies among them. Particularly, there is not a consensus on the wave period effect in ripple evolution and equilibrium geometry. In this study, a Eulerian two-phase model for sediment transport applications, SedFoam, is utilized to study the ripple evolution in response to step-changes of the oscillatory flow mimicking the surface waves. The model successfully simulates ripple evolution and resulting equilibrium geometry for different initial bed profiles and combinations of flow period and intensity. Model results explain the importance of the wave period as it determines the primary vortex structure, which further controls the ripple geometry. Results also confirm that the role of near-bed load transport and suspended load transport in growing and diminishing of sand ripples.