3-D Numerical Simulation Of Tidal Flow And Sediment In Coastal Zone

Three essentials must be considered when studying on estuary and coastal sediment movement, dynamic factors of estuarial and coastal areas, characteristics of sediment and factors of engineering environment. Each of them is aggregate of multiple factors and many problems exist in both the theory and approach, which makes it rather difficult to study on the sediment motion of estuarial and coastal areas and actually it has become one of the most difficult problems in the estuarial and coastal dynamics. The current primary research methods are theoretical research, experiment in laboratory, field observation and numerical simulation. The kinetic characteristics of the nearshore tidal flow and the sediment as well as numerical simulation on them are discussed in this dissertation with the main points as follows.1. Analysis on the characteristics of sediment motion. The flow scouring force method and the bottom shearing stress method are two primary means to research on this problem at present. However, those two methods are different in physical meanings and mathematic expressions and have not been unified for the moment. The sediment resuspended flux and deposited flux in both two methods are compared and analyzed. The similarities and differences of different expressions about the sediment bottom boundary condition are discussed. The corresponding parameters of those two different methods are analyzed. Some suggestions are put forward for further research on the sediment movement bottom boundary of estuarial and coastal areas.2. Tidal flow and sediment mathematic model. The motion of the tidal current and sediment of estuarial and coastal areas has three-dimensional characteristic in nature. Thus 3-D mathematic model can reflect this characteristic and the complicate exchanges between suspended load and bed load reasonably. Based on analysis of the present tidal flow andsediment mathematic model of estuary and coastal, a 3-D model which can describe the characteristics of estuary and coastal tidal flow and of sediment are presented as well as the initial or boundary conditions. Numerical discretization is also performed.3. Model application. Much difficulty exists when applying the 3-D model of tidal current and sediment into practical sea area such as the imperfection in theory, complicate variations in hydrodynamic factors and uncertainties in the sediment boundary conditions. Based on the analysis of characteristics of estuary and coastal hydrodynamic and of sediment motion, the calculation of tidal flow and sediment motion in coastal areas around Rizhao Port is drawn as an example. 3-D distributing of tidal current and sediment in this area is calculated through the rating of computation parameters in actual landform. The results show its accordance with the practical situation. The application of 3-D tidal current and sediment mathematic model in practical sea area, from theory and approach respect, is discussed.The sediment problems in estuarial and coastal areas have attracted much attention from scholars as the increasing undertakings in construction in this field. The erosion and deposition problem on the sediment bottom boundary layer and the numerical simulation approach of this problem is one of the research emphases. Based on the summarization and analysis of the research findings of sediment mathematical model both home and broad, the characteristics of estuarial and coastal areas tidal current and of sediment are analyzed and discussed as well as numerical simulation on it. These are applied into practical sea area and some satisfied results are obtained. These research findings have both theoretical and applicable value for estuary and coastal sediment movement.