Hydrodynamic performance of a dual-row multi-chamber OWC-integrated floating breakwater with bottom-mounted baffles

To reduce the construction and operational costs of offshore wave energy utilization, this study proposes an integrated system consisting of a pile-guided floating pontoon breakwater equipped with dual-row multi-chamber oscillating water column (OWC) devices and bottom-mounted baffles. The system is designed to achieve simultaneous wave energy capture and wave attenuation. An efficient three-dimensional model based on the higher-order boundary element method (HOBEM) is developed to account for hydrodynamic interactions among the chambers and their coupling with pneumatic processes and structural heave. The numerical results show that enhanced pneumatic power capture can occur alongside reduced local wave amplitudes in the leeward monitoring region. The multi-chamber configuration significantly improves the energy capture performance, and the peak efficiency of the four-chamber configuration is nearly three times that of the single-chamber case. Chamber dimensions and pneumatic damping are found to play important roles in controlling the operating bandwidth and capture efficiency. In addition, bottom-mounted baffles enhance both wave energy capture and attenuation performance by concentrating wave energy around the OWC chambers and suppressing wave propagation beneath the structure. Furthermore, heave motion has distinct effects on the two chamber rows. It generally weakens air–water coupling and reduces pneumatic capture in the waveward chambers. In the leeward chambers, however, heave-induced relative motion between the chamber and its internal water column can become the principal driver of airflow and pneumatic power capture under short-period conditions, when direct wave excitation is weak. At longer periods, stronger heave can instead reduce pneumatic capture in these chambers. Overall, the proposed system shows considerable potential as a multifunctional offshore structure for renewable energy harvesting and coastal protection.