Hydrodynamic characteristics of a box-type floating breakwater with restrained piles under regular waves

Abstract

Floating breakwaters are essential for protecting inner waters and coastal shorelines. In this study, a series of experiments and 2-D CFD numerical analysis was conducted to investigate the hydrodynamic performance of a box-type floating breakwater (BFB) with restrained piles in regular waves. The wave reflection coefficient (Kr), wave transmission coefficient (Kt), wave energy dissipation coefficient (Kd), and average variation range of the pitching angle (θa) were explored with wave and BFB property parameters. It was found that with increasing incident wave steepness for a given wave period T, the Kr and Kd values decrease; however, the Kt and θa values increase. In contrast, with increasing T, the Kr and Kd values decrease, and the Kt increases. θa reaches a maximum value when T approaches the natural period of the pitching box. With increasing still water depth for a given relative water depth scenario, the Kt decreases; however, the Kr and Kd values increase. With increasing relative width of pitching box, the Kt decreases slightly, and the Kd and θa values increase to some extent. Furthermore, the least squares and dimensional analysis methods were used to obtain the prediction formulas of Kr, Kt and Kd with acceptable accuracy.