A novel concept for reducing wave reflection from OWC structures with application of harbor agitation mitigation/coastal protection: theoretical investigations

Oscillating water column (OWC) device has the potential application in the field of harbor agitation mitigation/coastal protection. In this paper, we present a theoretical study on the hydrodynamic performance of a novel coastal structure, which combines a conventional harbor/coast-based single-chamber OWC device and a surface-piercing perforated barrier. Based on the linear potential flow theory, a semi-analytical model for wave interaction with the novel coastal structure is developed. The influence of the geometrical/physical parameters on hydrodynamic characteristics of the novel coastal structure is revealed. The results show that, by implementing the perforated barrier, a remarkable reduction of wave reflection from the OWC device can be achieved, without the compromise of the hydrodynamic efficiency. The incident wave energy is absorbed by the OWC device in the low frequency region and is dissipated by the perforated wall in the high frequency region. Comparisons of the conventional OWC structure and the proposed structure indicate that the frequency bandwidth for effective wave attenuation is broadened. In addition, the location of the perforated wall is identified as a key parameter influencing the hydrodynamic performance of the novel coastal structure.