Comparison of numerical and experimental analyses for optimizing the geometry of OWC systems

There is a considerable amount of wave energy that can be extracted from the oceans. This energy is largely untapped. Oscillating Water Column (OWC) is a mechanical system that utilizes fluctuating water level from sea waves to drive an air turbine which, in turn, provides electricity when transmitted to a generator. In this study, two sets of modeling, each involving a numerical modeling and a physical experimental modeling, were conducted in a wave flume to optimize OWC systems. By varying the length, width and angle of the air chamber, an OWC structure can be designed to obtain the maximum system power. The data used for designing the optimal geometry of the chamber that may yield the maximum conversion of wave energy to useful energy were provided from the interpretation of the measurements of these parameters. In this study, results of the numerical models were compared with the measured experimental values based on the Nash-Sutcliffe coefficient of efficiency (NSE) as performance evaluation criterion. The NSE values of both the classical and the modified OWC structures were obtained to be 0.97. It is observed that the results of the numerical models tend to follow much closer the results of the experimental model.