Hydrodynamic performance characteristics of an oscillating water column device integrated with a pile breakwater

The hydrodynamic performance characteristics of an oscillating water column (OWC) device mounted on a pile-supported breakwater (OWC-PSB) exposed to action of regular and random waves is investigated. The results are compared with that of a vertical wall type pile-supported breakwater (VW-PSB). The experiments were carried out in a wave flume in a constant water depth of 0.95 m covering intermediate to deepwater conditions. The wave energy transmission past both models is found to be similar under deepwater conditions, and marginally less for OWC-PSB in intermediate water depths. The OWC-PSB model exhibited less wave reflection for most of the tests. Since a part of incident wave energy is converted to water column oscillations inside the OWC chamber, the energy dissipation co-efficient for OWC-PSB is more than that for VW-PSB. The wave amplification factor for the OWC device is higher for long waves; however, the hydrodynamic efficiency is higher for high-frequency waves with the efficiency being a maximum close to 50% under deepwater conditions.