A simplified approach to optimize wave attenuation for floating energy islands: the role of flat plates

Floating offshore energy islands represent a promising solution for large-scale renewable energy pro- duction, especially in semi-enclosed seas like the Mediter- ranean. However, one of the main challenges in deploying such systems is ensuring wave attenuation to create shel- tered marine areas. To address this challenge, this study evaluates the hydrodynamic performance of a box-type floating breakwater equipped with flat plates, designed to improve both wave attenuation and enhance stability. A simplified 2D numerical model is developed, combining linear potential flow theory with Morison-type viscous terms to simulate the interaction between waves and the structure. Different configurations of the flat plates are tested and compared using transmission, reflection, and dissipation coefficients, as well as hydrodynamic damping, used to estimate the energy generation capability. The dissipation coefficient is evaluated through an energy- based method and calibrated using physical model tests and high-fidelity numerical simulations. Preliminary re- sults show that adding flat plates significantly reduces wave transmission and enhances dynamic stability, indicating the potential for dual-purpose use as both a breakwater and an energy-harvesting device. Further validation through physical studies is under development.