Assessing the impact of novel hybrid floating breakwater-WEC systems on hydrodynamic performance and sustainable energy outputs

Abstract

Developing novel low-reflection structures, such as Oscillating Water Column (OWC) wave absorbers, provides a promising solution for enhancing harbor berthing safety. OWCs present the dual advantage of reducing wave reflections while simultaneously capturing wave energy. This study experimentally investigates the reflection characteristics, efficiency of wave energy extraction, and power dissipation behavior of OWC absorbers with different rear wall configurations. Furthermore, it investigates variations in rear wall geometry, incident wave height, and the well turbine located inside the air chamber, which converts wave power into pneumatic power. Controlled wave flume experiments at the University of Port Said were conducted on four models. Key performance parameters analyzed include the dissipation coefficient (C_d), energy coefficient (C_e), transmission coefficient (C_t), reflection coefficient (C_r), and pressure coefficient (C_p). The effects of different draughts, water depths, and air pressure fluctuations inside the pneumatic chambers were also examined. Results indicate that rear wall geometry significantly affects reflection and dissipation rates. Model-D achieved optimal performance at a water depth of 0.30 m with a front wall draught (d₁) of 0.10 m, exhibiting low reflection (C_r = 0.139), high energy dissipation (C_d = 0.9), and a high wave energy conversion (C_e = 0.75; C_p = 0.85), making Model-D suitable for floating barriers in deep-water environments. Its superior wave energy dissipation enables effective operation under larger drafts and higher sea states.