Experimental investigation of array effects for a mechanically coupled WEC array

Tank testing is frequently used by wave energy converter (WEC) developers to analyse individual devices or even small arrays. In this set of tests a model of an individual device and an array, built up in a modular fashion from mechanically connected individual devices, were tested separately in order to evaluate the array effect on power production, power smoothness and mooring loads. A range of studies have addressed numerical and physical model testing of individual WECs and arrays of devices which interact hydrodynamically but are not mechanically coupled. This study investigates a 15 degree-of-freedom individual device and a 45 degree-of-freedom mechanically coupled array, such that an understanding of the array effects and in particular the effect of combined mechanical and hydrodynamic coupling on a multi-degree-of-freedom WEC array can be obtained. We show that the combination of mechanical and hydrodynamic coupling reduces the mooring load experienced per node for the array compared with the individual device, and in some conditions improves the power production and power smoothness beyond what is expected for an array of mechanically isolated devices.