A single oscillating rigid body is one of the earliest concepts of wave-energy device, for which some fundamental theoretical results were firstly derived by Evans [1]. An insight of the main concepts, including optimal power absorption conditions, was developed and summarized by Falnes [2]. These authors showed, in particular, that the maximum energy which may be absorbed by a heaving axisymmetric body equals the wave energy transported by the incident wave front of width equal to the wavelength divided by 2p. This upper limit may be achieved using an optimum control (“reactive control”).
Falnes derived also an expression for the power absorbed by an array of wave energy devices, adopting the so-called “point-absorber” approximation. Different analytic approaches [3] have been developed to account more accurately for the hydrodynamic interferences due to multiple bodies arrays. Boundary Element Methods (BEM) are nowadays a widespread tool to numerically model the interaction between waves and bodies and appear to be more and more efficient and accurate. An example of the utilisation of such methods is found in [4]. In this work the hydrodynamic coefficients are computed by the means of a BEM code (WAMIT) only on an oscillating mode (heave) in water of infinite depth. We will consider the response to monochromatic waves and subsequently to some simplified random irregular waves climate.
