Experimental Investigations of an Elastic- Membrane Integrated Oscillating Water Column Wave Energy Converter

In light of the adverse environmental impact of fossil fuels, transition to cleaner renewable energy resources is currently underway. The present research aims to contribute to the development of ocean wave energy converter (WEC) technology as a sustainable energy source. To achieve this goal, the objective of this work is to improve the efficiency of an oscillating water column (OWC) wave energy converter design by increasing the frequency bandwidth of power capture. To accomplish the bandwidth improvement, one option is to add another component to the traditional OWC with its own resonance characteristics. An integrated design of the elastic membrane with the conventional OWC (e-OWC) can potentially enhance the range of power capture across the bandwidth of wave frequencies. In our experiments, we use a rubber membrane as the new component to tune the natural frequency by adjusting its geometry and material properties. This study analyzes the experimental integration of the rubber membrane into a model-scale OWC device, exploring the elastic properties required to achieve the desired natural frequency alignment with full-scale wave characteristics. The investigation comprises two sets of experiments. The first set is the traditional standalone OWC and the second is the OWC integrated with a rubber membrane, the e-OWC. This allows for a comparison between the two designs to investigate changes in frequency response. The main contribution of the paper is the damped frequency response of the OWC compared with the e-OWC. It is shown that the e-OWC enhances the CWR at resonance. Therefore, the inclusion of a well-designed elastic membrane proves to increase the efficiency of the OW C approach to wave energy conversion.