Investigation of the floating IEA Wind 15 MW RWT using vortex methods Part I: Flow regimes and wake recovery

Floating wind turbines have the potential to enable global exploitation of offshore energy, but there is a need further understand complex aerodynamic phenomena they can encounter due floater induced rotor motion. Aerodynamic models traditionally used in energy sector, like Blade Element Momentum (BEM) theory, may not be capable capturing dynamic that occur when moves and out its own wake. In present paper, we therefore compare an industry standard BEM-based code state art vortex solver, investigate detail clarify capabilities limitations both methods. An initial benchmark two codes using IEA Wind 15 MW RWT mounted on WindCrete spar-buoy carried out. Three different scenarios are taken into account: bottom-fixed, floating case, case subject regular waves. Growing discrepancies between been observed with increasing complexity simulations. Moreover, large differences wake generated by bottom fixed turbine observed, latter one experiencing faster recovery. To explore behaviors affect performance wake, systematic investigation mean tilt angle influence development has Further, account for oscillatory motion turbine, parametric study where prescribed pitch surge degrees freedom (DoF) designed. The covers variety scenarios; wide range relevant frequencies amplitudes under above-rated conditions. A total more than 28 unique cases defined simulated fidelity models. results include downstream evolution recovery intensity turbulent disturbances rotor. generic nature allows characterize flow effects enables subsequent generalization designs given natural frequency amplitude. It found BEM LL predictions maximum loading blade root tower quite well, except oscillation above rated conditions, method under-predicts loads. use solver makes it possible look depth characteristics, which bottom-fixed non-turbulent inflow amplitude oscillations strong impact link short time intervals FA tip displacements break down Finally shown fast transition states, including non-conventional propeller ring identified characterized.