Validation of Theoretical Performance Results using Wave Tank Testing of Heaving Point Absorber Wave Energy Conversion Device working against a Subsea Reaction Plate

The aim of this study was to validate different theoretical performance models using subscale wave tank tests. The device modeled is a heaving point absorber working against a submerged reaction plate. This type of device has been pursued by a number of commercial and is therefore relevant as a benchmark for future efforts on similar devices. A set of model tests were carried out at 1:33 scale in the hydraulic laboratory at Scripps Institute of Oceanography. Wave periods between 5 and 20 seconds were selected to test the response of the model to sinusoidal waves. This corresponds roughly to the range of wave periods encountered at most deployment sites of interest globally. A novel viscous damper was developed as part of the project to represent the power take-off, which provides a means to model a power take-off with virtually no friction and a very predictable behavior. This is an important consideration when trying to correlate wave tank tests and theoretical models. Two theoretical models (1DoF and 3DoF) were developed in the commercial code AQWA and their results were compared to the model tests. Finally, a wave to wire model was developed to compute annual power production at a target deployment location in Northern California allowing for benchmarking of the machine. The results show that good agreement between theoretical models and model testing can be attained if viscous drag terms are represented accurately.