Experimental analysis of a model floating wind turbine under controlled conditions

Abstract

Up to date most of the research on Offshore Floating Wind Turbine (OFWT) concentrated on the dynamics of such systems. In the absence of experimental data, studies on OFWT aerodynamics have until now been restricted to numerical modelling based on free-wake vortex methods and CPD. Significant motions of the platform affect the formation of the helical geometry of the wake. Understanding the complex aerodynamic behaviour of such wind turbines due to the combined actions of the wind and waves is vital to be able to simulate the aerodynamics of OFWT's. A model OFWT was set up in a wind/wave generating facility and measurements were undertaken under controlled experiments. The model OFWT was subjected to a fixed wind speed and one dimensional intermediate/deep water waves; three different blade pitch angle were used. Initially experiments were carried out to measure the distinct performance characteristics when the wind turbine was operated with fixed foundations and when floated freely under the action of the waves. Wake measurements were then undertaken using hot-wire anemometry to study how the performance characteristics were influenced by the wake behind the floating wind turbine.