The Oscillating Water Column (OWC) device is recognized as one of the most promising Wave Energy Converters (WECs) for its high efficiency and structural simplicity. Dual-chamber OWC-WEC has been considered as the one with more apparent advantage of capturing wave energy than the single-chamber device. Therefore, the paper presents an experimental study, which was performed in a wave-current flume at State Key Laboratory of Coastal and Offshore Engineering of Dalian University of Technology, on the hydrodynamic performance of a 3D offshore-stationary dual-chamber OWC device with cylindrical type. The single-chamber OWC device is also included for comparison in the experiment. The optimal power taken-off (PTO) damping is simulated by using an orifice on the ceiling of the air chamber. It is found that the dual-chamber OWC can increase the hydrodynamic efficiency in the resonant frequency domain in comparison with the single-chamber one. Then, the effects of the drafts of two sub-chambers are discussed with the different incident waves. It is observed that a proper set of two sub-chambers drafts can enhance the OWC hydrodynamic performance in the high-frequency domain.
Renewable energy has been recognized as one of the most optional choice to cope with the increasing costs of fossil fuels as well as economic development. Ocean energy, especially wave energy, has drawn people's attention as an important type of renewable energy (Dizadji and Sajadian, 2011). Among various WECs (Borthwick, 2016; Musa et al., 2017; Martins, 2018), the OWC device is considered as one of the most favorable wave energy converters (Delauré and Lewis, 2003). The OWC-WEC has been studied by a lot of researchers for its survivability and maintenance convenience. Up to now, many OWC concepts have been proposed and tested in prototype, such as the Pico plant (400KW) in Portugal (Falcão, 2000), the Islay plate (500KW) in Scotland (Healt et al., 2000), the Oceanlinx MK3 (2.5MW) in Australia (Falcão and Henriques, 2016), and the shoreline OWC (100KW) in China.