A prototype point absorber style wave energy converter has been proposed for deployment off the West coast of Vancouver Island near the remote village of Hotsprings Cove in Hesquiaht Sound;​ a site identified as having significant wave energy potential. The proposed design consists of two components, a long unique cylindrical spar and a concentric toroid float. To serve ongoing wave energy converter (WEC) dynamics modelling and control research in support of that project, an experimental facility for small scale physical model testing is desired at UVIC. In the immediate term, the facility could be used to determine the hydrodynamic coefficients over a range of wave frequencies. Refined estimates of the hydrodynamic coefficients would be exploited in the optimisation of the WEC geometry. To date, WEC research at UVIC has neglected the frequency dependence of the hydrodynamic coefficients, relying on limited experimental results to provide a single frequency invariant set of coefficient estimates.

The research detailed in this thesis was focused on developing an experimental testing system to characterize the hydrodynamic coefficients for added mass and damping for a point absorber type wave energy converter. The point absorber design consists of two main components whose geometry interacts with the surrounding fluid, the deep cylindrical spar and concentric toroidal float. The design is representative of the technology being considered at Hesquiaht Sound. An initial batch of experiments was also conducted for a scale model of one design of the wave energy converter. The program of study included the design and manufacture of the wave tank and the WEC scale model, a validation of the facility against existing hydrodynamic coefficient predictions for simple floating geometries, and hydrodynamic characterization experiments in which the lumped parameter hydrodynamic coefficients were identified for the scaled model WEC and comparison of the results to existing simplified models at UVIC.

The development of the test facility first involved ascertaining and accommodating the constraints of an existing fluid tunnel that had to accommodate a wave maker and the physical WEC models. The test facility incorporated a low friction mechanism to maintain single degree of freedom motion, heave, for the WEC model motions. A forcing mechanism was created for the generation of sinusoidal, linear, oscillations of the model;​ a piston style wave maker was also constructed for the generation of sinusoidal, linear waves. Measurement transducers for the wave regime, hydrodynamic loading and the model motion were installed including:​ a wave gauge, a torsional load cell and a 3D camera, respectively. The facility is designed to accommodate four different experiments:​ a naturally damped oscillation in quiescent fluid, a forced oscillation of the model components in quiescent fluid, free oscillations driven by a generated wave field, and fixed model tests in a generated wave field. The quiescent fluid methods were used to identify the reactionary forces, whereas the wave field tests allow for the identification of the excitation force coefficients. Three model arrangements were considered:​ a simple cylinder for validation purposes, the WEC spar alone, and the spar with a fixed or motionless float. The wave regime generated in the 3rd and 4th tests were a scale replication of wave data previously identified at UVIC for the Hesquiaht Sound WEC deployment site location. To determine the coupling effects between components of the scale model WEC, the spar hull was tested in isolation and with the outer concentric float present.

The experiment established that the test facility is sufficient for the desired scale range for the three methods tested, based on comparison with an established numerical results for the simple cylinder geometry. The experimental data indicates that the numerical model utilized for simple cylinders cannot be used for the unique spar geometry. The non-dimensional lumped added mass hydrodynamic coefficients for the spar in the presence of the float were found to be overall lower than when the float is absent, although different trends were identified for wave field versus quiescent fluid. The nondimensional lumped damping hydrodynamic coefficient was higher for the spar alone configuration than the spar-float model configuration in the wave field experiments but lower in quiescent fluid.