On the impact of motion-thrust coupling in floating tidal energy applications

Floating systems provide an opportunity to expand the available tidal stream energy resource and reduce levelised cost of by increasing number viable deployment sites; simplifying installation, maintenance decommissioning; accessing greater flow speeds near free surface. However, inevitable exposure surface conditions raises questions over both power delivery survivability these systems, due presence waves associated excitation floating structures. Without addressing concerns through scale modelling in laboratories prototype deployments, risk investors is too high gain significant support for industry. Therefore, this paper presents physical analysis a 1:12 model Modular Tide Generators platform concept, pseudo-generic design consisting catamaran-style platform, catenary mooring system submerged horizontal axis turbine. The behaviour full explored range wave, current, following wave–current conditions; with without turbine; rigidly fixed moored configurations. results imply that linear superposition currents adequate approach determining mean cyclic values loads motion system. loading on, generated by, turbine are more complex have implications quality lifespan In particular, magnitude increases current speed, as well surge pitch which observed be most influential harmonics resonance frequency. • Incremental laboratory tests proposed concept presented. Mean equilibrium altered but insensitive. Cyclic load speed interactions. Platform amplifies especially at peak harmonics. Motion-thrust coupling sensitive relative phases wave.