Computational Fluid Dynamics Modeling of Oscillating Water Column with Wells Turbine and Permanent Magnet Synchronous Generator for the Gulf of Thailand

The Gulf of Thailand presents a mild but consistent wave energy resource that remains largely untapped. This study investigates the hydrodynamic and aerodynamic performance of a breakwater-integrated Oscillating Water Column (OWC) coupled with a Wells turbine and a 10 kW direct-drive Permanent Magnet Synchronous Generator (PMSG). A comprehensive 3D Computational Fluid Dynamics (CFD) wave-to-generator model was developed using Ansys Fluent. The Volume of Fluid (VOF) method tracked the air-water interface, while a 6-Degrees of Freedom (6-DOF) dynamic mesh technique resolved the true transient acceleration of the turbine rotor. Regular 5th-order Stokes waves (H=0.5 to 2.5m, T=4 and 6s) representing shallow water conditions (depth 10 m) were simulated. The coupled electro-mechanical results demonstrated that under the damping of the PMSG, the turbine operated stably at loaded rotational speeds of 254–340 RPM, safely mitigating free-wheeling overspeed. Notably, the system delivered an average electrical power of 4.37 kW under mild sea states (H=0.5m) due to a hydrodynamic funneling effect between the detached breakwaters and the OWC structure. Conversely, under extreme monsoon conditions (H=2.5m), the average power saturated at 5.08 kW (with a 7.71 kW peak) due to wave breaking and destructive interference from strong backwash. These findings validate the techno-economic feasibility of integrating OWC systems into existing coastal infrastructure to maximize energy extraction in low-wave-energy climates, offering a sustainable power solution for coastal microgrids in Southeast Asia.