ON THE REAL TIME HYBRID MODELLING OF FLOATING OFFSHORE WIND TURBINE USING DUCTED FAN(S)

Real-time hybrid modelling refers to the use, in real-time, of multiple modelling approaches to improve the overall accuracy of the representation of a complex system. In hydrodynamics, numerical models may not be able to capture non-linear effects such as viscous effects, greenwater, slamming, second or higher order loads and usually require calibration against basin model tests. On the other hand, the downscaling needed for the model test is difficult to achieve for a system submitted to both hydrodynamic and aerodynamic loadings. For some applications, couplings between the individual system components are so large that testing separately each component is not representative of the global system's behaviour. For such applications, the real-time hybrid modelling, mixing in real-time (i.e. in the basin itself) numerical simulations and basin model tests, can solve this issue. This paper presents the application of such technique to a floating offshore wind turbine. The first basin tests were performed with a single fan and a turbine numerical model with rigid blades. For the second set of tests, the following improvements were made: on the experimental side, a dual rotating fans system was built and on the software side, the influence of blade flexibility was incorporated. Comparisons between the various modeling assumptions and experimental setups are presented. This is useful to define the required level of turbine representation based on the objectives of the basin tests.