Three-Dimensional Numerical Simulation Of Overtopping On Breakwaters

Sloping breakwaters is an important structure that protects coastal areas from storm surges and waves.When the wave in propagation encounters the obstruction of breakwater,the wave overtopping often occurs,which may cause structure failure and affect the facilities after the breakwater.So it is very important to accurately simulate the process of wave overtopping.Previous researches on overtopping of sloping breakwaters under the oblique waves werenot abundent.In the present thesis,a three-dimensional numerical wave flume with seepage is developed,and the interaction between the oblique waves and the sloping breakwater armored by accropode blocks is investigated through numerical simulation.The main contents and conclusions are as follows.(1)Through a series tests,optimal time and space steps are chosen for the simulation of irregular wave.It is fine to take 30 meshes within the scope of double significant wave heightaround the still water level and to keep the spacing of rest vertical meshes gradually increasing.The space step in horizontal direction can take the wave length from the peak period divided by 200.The time step can dynamically vary with the maximum step of the peak period divided by 50 while the Courant number is limited less than 0.5.(2)The parameter setting of seepage effect is optimized,and the empirical formulas more suitable for calculating the linear and non-linear terms in Darcy-Forchheimer equation are obtained.The proper turbulence model is chosen for overtopping simulation.(3)The full-scale simulation of the accropode blocks as armour layer of sloping breakwater is carried out through mesh generation tool.The interaction between the normally-incident irregular waves and the sloping breakwater armored by accropode blocks is investigated through numerical simulation.The results indicate reasonably good agreement both between the simulated mean overtopping rates and physical model results and between the simulated overtopping rates for full-size prototype breakwater and the prototype results converted from the model test based on the gravity similarity.It is concluded that the developed numerical model can be used to describe the overtopping process of sloping breakwater armored by accropode blocks under working conditions.(4)A series of examples are designed based on an actual sloping breakwaters.The interaction between the oblique waves and the sloping breakwater armored by accropode blocks is investigated,and the average overtopping and single wave overtopping under oblique wave are analyzed.