Combining offshore wind and wave energy converting apparatuses presents a number of potentially advantageous synergies. To facilitate the development of a proposed floating platform combining these two technologies, proof of concept scale model testing on the wave energy converting component of this platform has been conducted. The wave energy component is based on the well-established concept of the oscillating water column. A numerical model of this component has been developed in the frequency domain, and the work presented here concerns the results of this modelling and testing. The results of both are compared to assess the validity and usefulness of the numerical model. Keywords: wave energy; oscillating water column; tank testing; modelling; passive control Nomenclature:A ∈ R DoF ×DoF = Frequency-dependent added mass matrix (kg). Z ∈ R DoF ×DoF = Complex impedance matrix.

This study describes the application of the techniques of stochastic modeling to random data obtained from the sea trials of the wave energy device Kaimei, and the interpretation of the results in terms of device efficiency. Two models of the power absorption system are developed and the relationships derived between them yield information on the influence of the vessel motions on the absorbed power. The theory of multiple frequency response functions is applied to the data, and it is shown that the motions of the Kaimei have a detrimental effect on its energy absorption capacity and the reasons for this are investigated.