| With the rapid development of China's transportation, the sea-crossing bridges have been put forward in both medium-term and long-term planning of national railway network and highway network. Following the service of Donghai Bridge and Hangzhou Bay Bridge, Bohai Bay Bridge, Huangdao Bridge and Zhoushan Mainland- Islands Link Project etc have been put forward on the schedule. Four sea-crossing bridges including Bohai Bay Bridge, Hangzhou Bay Bridge, Lingdingyang bridge and Qiongzhou Strait Bridge will be constructed in Tong-San line, which is one of national south-north trunk highway main arteries, and is about 5200 kilometers long. The suspension bridge scheme and the long span cable-stayed bridge scheme have been adopted in Tong-San line and other sea-crossing projects. All of these suggest that the super-long-span sea-crossing bridges will be widely built in our country.Due to the long span, long cable and flexible structure, the coupled vibration of vehicle and bridge, cable vibration, wind and seism resistance etc. have become the most significant subjects in the study of cable-stayed bridge. The vibration analysis of the long span sea-crossing bridges will be even more complex, when the pier is in the deep sea, the bridge could have large vibration by suffering large wave force and the vibration could be coupled with other form of vibrations, which may cause the destruction of the bridge. In this thesis, first of all, a three dimensional numerical model of the interaction of wave and structure is established based on the concepts of two-phase flow, VOF method and spatially-filtered incompressible viscous fluid equations with LES model, and the waves interaction with structures are studied by developing and applying the numerical model. Secondly, the nonlinear movement equation of coupled vibration of cable and bridge deck of long-span cable-stayed bridge are deduced, and the characteristic of coupled vibration of cable and bridge deck was studied. Finally, the influence of cable local vibration on dynamic characteristic, wave response of cable-stayed bridge and the vibration of cable under wave effect are studied respectively. The main research includes the following several aspects:1.In order to investigate the wave interaction with piers,3D numerical wave model will be established. The free surface tracking method is one of the key techniques in developing 3D numerical wave model. VOF method and Level Set method are introduced in chapter two, and the PLIC-VOF method is introduced with excruciating particularity. The determination of normal vector of free surface, the determination of donor cell, the propagation of the interface and the computation of VOF flux are studied.2. Based on the concepts of two-phase flow, PLIC-VOF method and spatially-filtered incompressible viscous fluid equations,3D numerical model of the interaction between wave and structure is established. The Visual Boundary Force Method and Two-step Boundary Pinpoint Method are adopted to treat the boundary of the structure. Waves are generated at the boundary, which can simulate all kinds of theoretical waves such as small amplitude, stokes wave etc..Two-step projection method is used in the solver. The advection term is discretized by combining the upwind and the center difference and the other derivates by center difference.3.The application research of the wave interaction with structure is performed. First of all, the method of wave generated at the boundary and PLIC-VOF method have been validated by numerical simulation. Secondly, the flow field, vortex, drag coefficient and lift coefficient for the 3D flow around a vertical cylinder is studied. Thirdly, the wave diffraction and wave reflection for a wave interaction with a large scale vertical cylinder are investigated. And then, the wave interaction with a vertical rectangular pile, the wave interaction with arc-pier and the wave interaction with vertical cylinders are researched. The results show the wave profile is consistent with theoretical results. The model can simulate the wave interaction with structure. Wave reflection and wave diffraction are successfully simulated. Drag coefficient and lift coefficient have good agreement with other available literitures in the research of 3d flow around a circular cylinder, and very good correlations of the wave amplification factor between the present results and the analytical solution in the study of linear wave diffraction around a large vertical circular cylinder.4.To investigate the cable local vibration, the coupled vibration model of cable and bridge deck was established, and then, the coupled vibration of cable and bridge deck, coupled vibration of the two cables in close vicinity are respectively studied by numerical simulation. The results show that the resonance is found not only when the frequency ratio is 1, but also when the frequency ratio is 2 and 1/2. With the increase of the cable obliquity and the mass ratio, the resonance amplitude will decrease in evidence when the ratio of frequency is 1, but the resonance amplitude will increase when the frequency ratio is 1/2 and 2. There is a relatively wide resonance zone when the frequency ratio is 1, and the two cables in close vicinity will have biggish amplitude vibration when the frequency ratio of bridge deck and one of the two cables is 1.One of the two cables in close vicinity occur the parametric vibration, then, the other will have biggish amplitude vibration when the nature frequency of the two cables are close vicinity.5. The dynamic response of long span cable-stayed bridge and the coupled vibration of cable and bridge under wave effect are investigated. The results show that the response of girder acceleration and the response of girdr moment of side span are larger than that of main span, so the influence of wave force is more obviously on side span because of many assistant piers in side span. The largest tower acceleration is on the top of tower, and the tower acceleration will be attenuated in the cable zone of tower. The response of tower moment in the long cable zone is larger than other places of tower. The response of vertical displacement of the cables that have the close frequency with bridge are enlarged under wave effect.Finally, the research work of this thesis is summarized, and further research problems are indicated.
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