The influence of parameters on the hydrodynamic characteristics of oscillating water column devices: A numerical study

The influence of parameters on the hydrodynamic characteristics of OWC (oscillating water column) devices exhibits a coupling phenomenon, which is frequently neglected. To elucidate the comprehensive influence and its mechanism of structure parameters on the hydrodynamic characteristics of offshore OWC devices, a structure with a bottom plate was selected in this study. Through numerical simulation, the hydrodynamic characteristics of the chamber with variations in PTO (power take off) coefficient alpha, chamber length B-s, internal depth J(n), and under water length of front wall J(e) with different wave conditions are investigated. The following conclusions are primarily drawn: The research method of using the relative wavelength L/B-s as a non-dimensional parameter and solely varying the wavelength L has its drawbacks. In cases that L/B-s is held constant, the efficiency of chambers differing only in B-s can vary by more than 70%. The influence of each parameter on the effectiveness is interrelated. Chambers with a lower alpha exhibit a more pronounced impact of B-s. The efficiency of device with a smaller relative wavelength L/B-s is more significantly affected by the J(n). The mechanism by which the parameters affect efficiency is primarily since chambers with shorter B-s or greater J(n) exhibit smaller deformations during internal liquid surface oscillation, resembling a more uniform oscillating water column. This allows more energy to be utilized for pushing air in and out of the chamber above, thereby enhancing the energy conversion capability. The results of this research can provide valuable insights for the design of OWC devices.