Effects of WEC Array Layout on Motion Suppression and Power Absorption of a Floating Tidal Platform Under Irregular Wave Excitation

Floating tidal platforms provide a flexible solution for offshore tidal–stream energy exploitation, but their wave-induced motions may affect platform stability, turbine operation and power performance. Integrating wave energy converters (WECs) with a floating tidal platform provides a potential approach to absorb wave energy and modify platform motions. However, the dynamic role of a WEC array attached to a floating tidal platform remains insufficiently understood, especially with respect to array layouts, power take-off (PTO)-induced coupling and absorbed power. This study investigates the effects of WEC array layout on the motion response and absorbed power of a catamaran-type floating tidal platform under irregular wave excitation. Three representative WEC array layouts, namely longitudinal, transverse and hybrid arrangements, were compared with a baseline platform without WECs. A coupled numerical model was established by combining frequency-domain radiation-diffraction analysis and time-domain simulations of mooring system and PTO dynamics based on ANSYS AQWA 2023R2. The hydrodynamic model was verified through code-to-code comparisons with OrcaWave 11.6, and the PTO power model was checked against published numerical results. The results show that the WEC array layout has a significant influence on both platform response and power absorption. Among the investigated layouts, the transverse array provides the most effective overall motion suppression, with average reductions of 36.83% in heave responses and 52.62% in pitch responses compared with the baseline platform. Frequency-domain results indicate that pure multi-body hydrodynamic interaction has a limited influence on the platform response amplitude operators (RAOs) and wave-excited forces, whereas time-domain results reveal much stronger layout-dependent responses once PTO coupling was included. The WECs’ absorbed power was strongly affected by the geometric relationship between the PTO rotation plane and the dominant platform motion plane. When these two planes were aligned in coplanarity, platform motion enhances the relative PTO rotation and increases output power. These findings indicate that, for floating tidal platforms with relatively small displacement, WEC arrays should be treated as distributed dynamic subsystems rather than only as energy-harvesting add-ons. The results can provide useful guidance for the layout design and coupled dynamic assessment of floating hybrid tidal–wave energy converters (HTWEC).