Dynamic Interaction Among Wave, Structure And Seabed

The study of dynamic response of the seabed around the structure is important for estimating the stability of the structure. The structure not only influences the waves nearby but also transfers the loadings to the seabed with impermeable boundaries. The water also flows in and out between the seabed and the waves. So to investigate complicated mechanism between the three fields, a coupled numerical model is established that can be applied to more general wave and structure forms.Based on dynamic Biot's consolidation theory, a seabed numerical model is established in which element-free Galerkin method is used for the discretization of space domain and Newmark scheme for time domain. To break the restrictions of mixed formulation problem, a simple and effective stabilized strategy is proposed and the results show that the oscillations of the pore water pressure can be significantly reduced by this strategy. The validity of the model is conducted by the comparisons between analytical solutions and computational results.The response of the seabed under wave loading is studied on the basis of the seabed numerical model. The content includes the parametric analysis of the permeability, shear modulus, the degree of saturation and seabed thickness; the influences of the inertia of the soil skeleton and pore fluid; the effects of the anisotropy and inhomogeneity; the seabed response under standing waves.A numerical wave model is established which governing equations are RANS with wave-making and wave-absorbing boundaries and VOF method for tracking the free surface. Numerical cases including linear and nonlinear progressive wave, and waves passing submerged breakwaters are used to verify the model. The results indicate the model can simulate strong nonlinear and dispersive properties of waves.A wave-structure-seabed numerical model is formed by coupling the seabed and wave numerical model and considering the structure. The computational results are compared with experimental data for the seabed without structures and for the seabed existing porous submerged breakwater and composite breakwater. Then dynamic characteristics of the wave and seabed field around the structure are discussed.