This paper presents a numerical study on an innovative system for converting
energy from waves. It consists of a point pivoted body which oscillates in presence of waves. The
system uses a linear electrical generator which converts floating movements of the
buoyant body into electrical power. The buoyant body floats, describing an arc, by means of two
hinges. A suitable Power Take-off Device (PTO) is placed between buoy support arms and the fixed
structure and has the function to convert the mechanical power of the linear
oscillating motion of the connecting piston into electrical power. A design assumption
is made on the PTO control system: PTO reaction force is assumed to be linearly dependent on piston
oscillation velocity with a given force-speed gain. This coefficient is strictly connected to
electrical generator characteristics and its value has an effect on power conversion
efficiency . A scaled model of this system has also been tested in the wave/towing
tank facility of Department of industrial Engineering (DII) of University of Naples “Federico II”.
A variety of numerical analyses, such as potential flow simulations and Unsteady Reynolds Averaged
Navier-Stokes (URANS) simulations, have been performed to predict the system performances.
Numerical and experimental analyses have included the performances of the baseline
geometry, both in free response and under wave excitation, in order to characterize the response of
the system, and results have been used to understand which parameters affect more the power
production. Finally a numerical optimization procedure has been carried out to optimize the
shape of the converter with the final objective of increasing the generated power,
eventually imposing a constraint on the amount of immersed volume. In this way, a modified
configuration has been predicted with higher power output and the same value of
submerged volume, but with different shape