Wave Force on the Crown Wall of Rubble Mound Breakwaters at Intermediate Depths

Rubble mound breakwaters with a crown wall are a common coastal engineering structure. The wave force on crown walls is an important parameter for the practice engineering design. Particularly, the wave force on crown walls under intermediate depths has been studied through physical model tests and numerical simulations. In this study, a three-dimensional numerical wave flume was developed to investigate monochromatic wave interactions in a rubble mound breakwater with a crown wall. Armor blocks were modeled in detail. The Navier-Stokes equations for two-phase incompressible flows, combined with shear stress transport k-ω turbulence model and volume of fluid method for tracking the free surface, were solved. A set of laboratory experiments were performed to validate the adopted model. Subsequently, a series of numerical simulations were implemented to examine the impacts of different hydrodynamic parameters (including wave height, incident wave period, and water depth) and the berm width on the wave force of the crown wall. Finally, a comparison of the experimental results and Martin method shows that the latter method is not suitable for this experimental scope. New empirical formulas are proposed to predict the wave force on crown walls under intermediate depth. The results can provide a basis for the design of crown wall of rubble mound breakwaters at intermediate depths.