Dynamic Analysis Of The Ship-water-chamber Coupled System Based On Viscosity

To consider the effect of the viscosity on the ship-water-chamber coupling system of the ship left, the present thesis derives the governing equations of the viscous fluid based on the theory of Rayleigh viscous coefficient (also called surface viscous coefficient in this thesis) and the non-linear water-wave equation. Using the perturbation theory the water-wave equation was divided into first order and second order velocity potential equations and the corresponding finite element matrix equations have been derived by means of Galerkin method. Furthermore, the general stiffness matrix was formed and the finite element matrix equations about the general displacement of the rigid structure were derived. The equations of the fluid and the rigid structure were combined into a new equation by using the variable parameters of water pressure.Second, a scale model of the ratio 1:50 to the real Three Gorge ship lift was created. This model was used to observe the vibration of the free surface under the different frequencies and viscosities, measure the amplitude damping along with time. This data is used to calculate the viscous damping rate. In the experiment, the linear relation of surface viscous coefficient and the system viscous damping rate is proven, consequently, the method about how to gain the value of surface viscous coefficient was found.On the basis of the experiment, the analysis of the whole fluid-solid coupled equation in the time domain is completed. Compared with the ship-water-chamber of the irrotational, incompressible, homogeneous fluid, the effect of the viscosity is not only on the rapid damping of wave disturbance, but also on smoothing the second order non-linear water wave.Last, many numerical calculations of the above work were performed and some interesting results were given.