Numerical Simulation Of The Stability Of Amour Blocks Of Rubble Mound Breakwater

The rubble mound breakwater is most widely used breakwaters, because it is easy to build, maintain and it has a good energy dissipation ability. Usually, these blocks, which may weight tens tons, can both remain structurally stable under the strong wave condition and dissipate wave energy. But when under extreme wave condition, these amour blocks may failure. The main failure mode is hydraulic instability and the breakage of amour blocks. Till now, the flow field and the energy dissipation within the amour layer of breakwaters are still poorly understood by researchers. The major method to study stability of breakwater is physic experiment. Unfortunately, due to the scale-effect, the hydraulic forces and the stress within the blocks can not be model correctly. So build a numerical model to study the stability of breakwaters becomes a focus reaching points.In this paper, a fluid solid interaction numerical model, based on smooth particle hydrodynamic(SPH) and discrete element method(DEM), is developed. The fluid field is simulated by improved SPH, which governing equation was corrected by CSPM and Riemann-solver. The solid boundaries, such as wave maker, tank bottom and tank right wall are simulated by wall particles. The motion and the interaction between blocks are modeled using Multi-Sphere DEM method. The accuracy of proposed two dimension SPH-DEM model was verified by experimental results. The interaction between wave and amour blocks was simulated using proposed model. The variation of fluid field during the process of wave shoaling and the pressure distribution along the slope are analyzed. The impact pressures when the wave slams on the parapet are also compared with the experimental results.Then, the two dimension SPH-DEM fluid solid interaction model was developed into three-dimension. A three dimension model building method, which based on the Computer Graphics Technology and unstructured mesh technology, is introduced to build three dimension numerical rubble mound breakwater. A three dimension complex region fluid particle fill algorithm is proposed. A parallel computing method based on OpenMP technology which can be used on multi-core shared memory computer is developed. Finally, a three dimension wave and amour blocks interaction example was simulated and the interaction force between wave, amour blocks and between blocks was analyzed. The research achievement of this paper proposed a new technology to design and optimize amour blocks.