2D Numerical Model Of Multi-fraction Fine Sediment Transport

Many coasts are composed of fine sediment in China, and many fine sediments are formed by mixtuere of silt and cohesive sediment. There exit great differences between the transport of silt and that of cohesive sediment, it is important to accurately simulate the mixed fine sediment transport for the harbor sedimentation and coastal evolution. Therefore, a numerical model for multi-fraction fine sediment transport under the combined action of wind, wave and current is developed to simulate mixed fine sediment. It is anticipated to provide useful information for solving the engineering problem such as channel siltation.The ADCIRC model for tidal current simulation and the SWAN model for wind waves simulation are firstly introduced. To compute the wave and tidal current accurately and take into account the interaction between waves and current, 3-layer nested models and iteration in the middle and small models are applied. The coupled hydrodynamic model considered the integrated action of wind, wave, tidal current and their interaction, so it could output accurate wave and current field and was verified by measured data in site.Based on the erosiong and deposition model and the advection and diffusion equation, a 2D numerical model for multi-fraction fine sediment transport under combined action of wind, wave and current are developed by the Finite Element Method. The numerical model is applied to simulate the channel siltation of Huanghua Harbor. Numerical results for the sediment transport and channel siltation due to strong winds, which occured before and after the regulation project respectively, show that the model can reflect the fact and can be used to guide engineering practice after refinement.