Hydrodynamic modeling of a novel dual-chamber OWC wave energy converter

A novel cylindrical oscillating water column (OWC) wave energy converter (WEC) with double chambers is proposed to harvest the wave energy effectively in deep water. An analytical model is developed to investigate its hydrodynamic characteristics based on the linear potential flow theory and eigenfunction expansion technique. The computational domain is divided into six sub-domains. The unknowns are solved by matching the continuous conditions of the fluid velocity and velocity potential between neighboring sub-domains. A pneumatic model is adopted to describe the relationship between the air pressure in the chamber and turbine characteristics. Effects of the chamber volume and parameters of the turbine on the energy conversion efficiency are investigated. It is found that the chamber volume affects the OWC hydrodynamics seriously in the case of large turbine rotating speed. Three typical free-surface oscillation modes in the chamber are found, two of which contribute much to the energy conversion. The comparison between results of the single- and dual-chamber OWC-WECs shows that the effective frequency bandwidth of the dual-chamber OWC-WEC is broader than that of the single-chamber OWC-WEC.