Development And Application Of A Dynamically Coupled Wave-current Model

Waves and currents are the main hydrodynamic factors in nearshore areas, and there is complex interaction between them. Therefore, the coupling of waves and currents should be considered when the numerical modeling of wave and current is carried out. Making use of the MCT (the Model Coupling Toolkit), a concurrent coupling model considering wave-current interaction based on the third-generation wave model SWAN and the three-dimensional unstructured grid FVCOM model, is developed and applied in the idealized and in-site example in the present thesis. The main contents and conclusions are as follows:1. Making use of MCT, a concurrent coupling model considering wave-current interaction based on SWAN and FVCOM is developed. The wave variables provided by SWAN are exchanged concurrently with the current variables provided by FVCOM in order to consider the wave-current interaction.2. The concurrent wave-current coupling model has been applied in an idealized case of tidal inlet, which is also simulated by offline coupling model. The change of wave field and current field has been analyzed. The results show that waves can be apparently influenced by currents. There is periodic change of waves under periodic currents. In addition, the computational efficiency of concurrent and offline coupling model were compared, and the consumed computational time of concurrent coupling model is less.3. The concurrent wave-current coupling model has been applied in the wave and current field simulation during the Typhoon WIPHA in2007. The model is verified based on the measured data and the tidal fields are analyzed during the typhoon process. The simulated results show that the concurrent coupling model can reveal the characteristics of the current field when the Typhoon WIPHA passed through the Lianyungang sea area. Wave and current fields all appear the rotary characteristics due to the rotating typhoon, but they occur with a delay of the typhoon center. Comparison with the pure current filed, the wind stress and wave radiation stresses have significant influence on the surface layer of current field, and the effect of wind stresses is the most significant. The wave radiation stresses also makes longshore current increase in the coastal area of the Lianyungang sea area.