Evaluating the Impact of Degrees of Freedom on the Hydrodynamic Performance of Sloped Floating Breakwaters: An Experimental Study

Abstract

This study experimentally examines the hydrodynamic performance of a sloped floating breakwater under two distinct configurations one involves a single degree of freedom (1-DOF) system, which is restricted to heave motion; the other involves a three DOF (3-DOF) system, which allows heave, surge, and pitch motions. The main objective is to investigate the effect of DOF on wave attenuation, which particularly explores reflection, transmission, and dissipation mechanisms. Experiments were performed in a wave flume at a geometric scale of 1:15 and under regular and irregular wave scenarios covering various wave heights and periods. Results indicate that the 1-DOF configuration presents superior wave attenuation performance at shorter wave periods, with transmission coefficients up to 14% lower than those of the 3-DOF system. By contrast, at longer wave periods, the 3-DOF configuration exhibits better wave energy dissipation, which achieves 4%–10% lower transmission coefficients. Analysis of Response Amplitude Operators suggests that the decreased heave motion detected in the 3-DOF system at longer wave periods is due to mooring-induced constraints and the interaction among multiple DOFs. This reduction in the heave response considerably contributes to enhanced wave energy dissipation. These outcomes emphasize the vital role of structural flexibility and DOFs in optimizing floating breakwater designs, which offer practical guidance for tailored solutions under diverse wave scenarios.

Keywords

Sloped floating breakwater / Degrees of freedom / Hydrodynamic performance / Experimental analysis / Transmission coefficient / Reflection coefficient / Dissipation coefficient

RIGHTS & PERMISSIONS

Harbin Engineering University and Springer-Verlag GmbH Germany, part of Springer Nature