A hybrid methodology for wind tunnel testing of floating offshore wind turbines

This paper is intended to present the authors’ know-how about hybrid/hardware-in-the-loop (HIL) wind tunnel testing of floating offshore wind turbines (FOWTs), that was acquired in the last decade through a very intense activity. Numerical codes commonly used within the scientific community to study FOWTs show significant uncertainties with respect to the prediction of some phenomena peculiar of these systems, like the rotorwind dynamic interaction or the coupling between the machine controller and the low-frequency rigid-body motion modes of the platform. A hybrid/HIL methodology was developed by the authors to exploit the unique characteristics of the Politecnico di Milano wind tunnel to collect data useful to improve the existing knowledge about the above mentioned scientific questions.