Numerical investigation of hydrodynamic performance and efficiency of a dual-chamber oscillating water column under different damping and chamber breadth ratio combination

Abstract

The dual-chamber oscillating water column (OWC) is a modified wave energy converter that has received considerable attention owing to its high capture efficiency and adaptability to wave conditions. In this study, the hydrodynamic performance of a land-based dual-chamber OWC was numerically investigated, focusing on the effect of damping combinations and chamber breadth on hydrodynamic efficiency. The commercial software ANSYS Fluent was employed to solve the Reynolds-averaged Navier–Stokes equation, and the solution was verified through a comparison with experimental data. The variations in water surface elevation, pressure, and efficiency of a dual-chamber OWC with different orifices and chamber breadth ratios were investigated. The results indicate that an OWC with different opening ratios is more efficient and offers advantages in adapting to variable wave environments compared with an OWC comprising two chambers with the same orifice dimensions. Furthermore, it was found that incident waves with a high frequency result in a higher absorption efficiency for the combination of smaller damping of the front chamber and larger damping of the rear chamber; by contrast, waves at lower frequencies have higher absorption efficiencies with the opposite combination. The breadth ratio has different effects on the hydrodynamic efficiency for different damping conditions. The findings can serve as a reference for the practical application of dual-chamber OWCs.