Experimental analysis of a water column and structure heave velocity relationship for a floating oscillating water column wave energy device

Abstract

This paper investigates the theoretical conclusions of a numerical analysis. The results are reproduced experimentally using a two-dimensional model in a wave flume. The experimental set-up is conducted by subjecting the model to waves with frequencies ranging from 0.2 to 2 Hz. The heave velocities of the structure and water column are calculated by differentiating the displacement of each with respect to time. The experimental results confirm that the extent of the parametric relationship between the structure heave velocity and oscillating water column heave velocity is linearly related to the power output potential of the system and hence, can be used as a design tool for floating offshore wave energy converters. It has also been determined that the extent of the parametric function is maximised when the forcing frequency is between 90 and 100% of the natural frequency of the water column of the system in question. This shows that the system efficiency is maximised when the waves cause resonance of the water column compared to the ocean wave.

Keywords:

• Energy
• power
• oscillating water column
• wave energy converter
• oscillating wave energy converter
• power capture
• OWC
• WEC

Acknowledgements

The authors would also like to acknowledge the University of Wollongong technical staff for their help in the laboratory.