An Experimental Study of the Hydrodynamic Behavior of a TLP platform for a 5MW Wind Turbine and OWC Devices VII International Conference on Computational Methods in Marine Engineering MARINE 2017 M. Visonneau, P. Queutey and D. Le Touzé (Eds) AN EXPERIMENTAL STUDY OF THE HYDRODYNAMIC BEHAVIOR OF A TLP PLATFORM FOR A 5MW WIND TURBINE WITH OWC DEVICES GEORGIOS M. KATSAOUNIS * , STYLIANOS POLYZOS * AND SPYRIDON A. MAVRAKOS † * Laboratory for Ship and Marine Hydrodynamics (LSMH) National Technical University of Athens (NTUA) 9 Heroon Polytechniou str., Zografos GR15773, Athens, Greece email: katsage@mail.ntua.gr, spolyzos@mail.ntua.gr † Laboratory for Floating Structures and Mooring Systems (LFSMS) National Technical University of Athens (NTUA) 9 Heroon Polytechniou str., Zografos GR15773, Athens, Greece email: mavrakos@naval.ntua.gr Hellenic Center for Marine Research, Director and President GR19013,Anavyssos, Greece email: mavrakos@hcmr.gr Key words: Floating wind turbine, Tension leg platform, Wave energy converter, Oscillating water column, OWC, Wave Tank experiments Abstract. An experimental study of the hydrodynamic behavior of a Tension-Leg Platform (TLP) for a 5MW Wind Turbine, featuring Wave Energy Converter (WEC) devices of the Oscillating Water Column type is presented. The examined triangular platform includes three vertical cylinders at the corners, providing the required buoyancy, each of them surrounded by a thin skirt, open at its lower end, forming the OWC chamber. A central vertical cylinder is included for the wind turbine installation. All cylinders are structurally connected with cylindrical bracing. The hydrodynamic response of the platform in the surge direction is experimentally verified, together with the resulting pressures and air fluxes inside the OWC chamber and the dynamic tensions in the lines of the mooring system. 1 INTRODUCTION The development of the offshore wind industry is inevitably linked to the challenge of installation of wind turbines at water depths above the range of 40-70 meters, an area where fixed structures can’t be economically installed and operated. For such depths, several designs have been proposed (spar buoys, floaters, semisubmersibles and tension leg platforms), many projects are in the final design stage or in the experimental testing of scaled down prototypes, while there are also some pilot full scale developments [1]. It is evident that the overall cost of a floating installation is increased, as compared against 722