A 3-D wave-current driven coastal sediment transport model

摘要

Most of the existing sediment transport models are not synchronously driven by both the wave field and the flow field. This paper describes a 3D sediment transport model with waves and currents directly coupled within the model to continuously account for different-scale activities especially those that have significant contribution to local sediment transport processes such as formation of sediment plumes and turbidity maxima. A practical issue in modeling coastal sediment transport, besides the concern of model accuracy, is the efficiency of the model. In the present model, the wave action equation, instead of the computational demanding elliptic mild-slope equation, is used to calculate the wave parameters. The wave action equations take into account wave refraction and diffraction as well as the tidal hydrodynamic modification. The calculation of the wave and current forcing is coupled during the time marching process so that the effects due to short-term activities can be considered. The model has been verified against laboratory measurements and has also been applied to simulate actual sediment transport situations in the Pearl River Estuary (PRE), China. It has been quantitatively shown that the suspended sediment concentration in the PRE increases significantly when waves are present. Sediment deposition occurs at the upstream region of the PRE while erosion takes place mostly at the down-estuary region due to exposure to wave actions.