Hydrodynamics of LIMPET type OWC device under Stokes second-order waves

This research aims to investigate the hydrodynamic performance and efficiency of the LIMPET oscillating water column (OWC) device. A two-dimensional numerical wave tank (NWT) is used in a fully nonlinear Reynolds averaged Navier-Stokes equations (RANS) model with the k - ! turbulence model for the Stokes second-order incident waves. A volume of fluid (VOF) method is utilized to capture the free surface elevation. The numerical simulation shows qualitative velocity vector and streamline profiles inside the chamber of the LIMPET OWC device across a whole pressure fluctuation cycle. It is found that the fluid particles with smaller velocity magnitudes are distributed throughout all directions, whereas the fluid particles with larger velocity magnitudes are aligned in one direction close to the orifice of the OWC device. Higher incident wave heights promote the additional vortex generation at the lower tip of the front wall of the device chamber. The specific dissipation rate is considerably higher as incident wave heights become higher, which demonstrates that the wave energy dissipation is higher for higher incident wave heights. The power produced by the LIMPET OWC device is higher for the incident waves having higher incident wave heights. In contrast, the efficiency of the OWC device depends on various parameters like incident wave height, water depth to wavelength ratio, pneumatic damping coefficients, etc.