Vortex ripple is widely formed in the coastal region, and the dynamic ofvortex is quite important because it is responsible for sediment transport. The flow structurearound the vortex ripples can be modeled as 2D flow...Vortex ripple is widely formed in the coastal region, and the dynamic ofvortex is quite important because it is responsible for sediment transport. The flow structurearound the vortex ripples can be modeled as 2D flow due to the geometry of the flow boundaries. Inthis paper, 2D Large-Eddy-Simulation (LES) method was used to predict the flow structure and thedynamic of vortex in the bottom layers under the action of the wave, the numerical simulationresults show a completely process of vortex formation, evolvement and disappearance. Based on thestudy of flow structure, the suspended sediment transport was modeled in present paper. Thesimulated sediment concentrations were compared to measurements from the literature. The agreementbetween the time averaged simulated concentration profiles and measurements is satisfactory. For ahigh setting velocity, the suspended sediment is confined to the vicinity of the bed, and it isdominated by the local bottom shear stress. For a small setting velocity, the suspension is moredominated by the characteristic of vortex. There are two suspended sediment transport peaks observedin the cross-section at the trough and crest in the half period, the second peak is due to theseparation bubble taking the sediment.展开更多
文摘Vortex ripple is widely formed in the coastal region, and the dynamic ofvortex is quite important because it is responsible for sediment transport. The flow structurearound the vortex ripples can be modeled as 2D flow due to the geometry of the flow boundaries. Inthis paper, 2D Large-Eddy-Simulation (LES) method was used to predict the flow structure and thedynamic of vortex in the bottom layers under the action of the wave, the numerical simulationresults show a completely process of vortex formation, evolvement and disappearance. Based on thestudy of flow structure, the suspended sediment transport was modeled in present paper. Thesimulated sediment concentrations were compared to measurements from the literature. The agreementbetween the time averaged simulated concentration profiles and measurements is satisfactory. For ahigh setting velocity, the suspended sediment is confined to the vicinity of the bed, and it isdominated by the local bottom shear stress. For a small setting velocity, the suspension is moredominated by the characteristic of vortex. There are two suspended sediment transport peaks observedin the cross-section at the trough and crest in the half period, the second peak is due to theseparation bubble taking the sediment.
