Using an Oscillating Water Column Structure to Reduce Wave Reflection from a Vertical Wall

Abstract

Wave absorbers are usually needed for reducing wave reflection from vertical walls. Different from traditional wave absorbers, which dissipate wave energy into unusable forms, an oscillating water column (OWC) structure can serve as a wave absorber with the potential to generate electricity. In this study, the hydrodynamic performance of a pile-supported OWC structure in front of a vertical wall was investigated experimentally. The surface elevations inside the OWC chamber were measured at two points for a better description of the motion of the OWC. It was demonstrated that the incident wave energy could be effectively attenuated by the OWC structure. Compared with the pile-supported slotted-barrier-type wave absorbers, the OWC-type wave absorbers could function as effectively as the slotted-barrier-type wave absorbers but with a potential to extract wave energy for electricity generation. The effects of the gap between the OWC structure and the vertical wall were examined, and the experimental results show that the existence of the gap reduced the energy-extraction efficiency and did not benefit the total energy dissipation. It is suggested that an OWC-type wave absorber should be constructed such that its rear wall is part of the vertical wall.