Note on Salter's energy absorber in random waves

Salter's wave theory energy device has been the object of extensive theoretical and experimental studies during recent years. This paper describes the performance of the device in random waves by means of a numerical study. Different situations are considered. First, the cam is allowed to have one degree of freedom (the cam rolls about a rigid and fixed shaft) and is in a shallow sea where the waves are modeled by the JONSWAP spectrum. Power extraction, efficiency and dynamic response are presented in terms of wind characteristics for a cam radius of 3 m. In the open sea where typical waves are longer and higher, waves are represented by the P-M spectrum and the cam radius is taken to be 7 m. Finally, it is shown for a particular set of design parameters how the efficiency decays and the power extraction decreases with lack of rigidity in the support system.