Experimental and numerically obtained low-frequency radiation characteristics of the OC5-DeepCwind semisubmersible

Added mass and damping play a significant role in accurate prediction of floating wind turbine (FWT) motions, especially near the resonance frequencies. This paper investigates still-water hydrodynamic characteristics semi-submersible FWT around natural periods surge, heave pitch motion. A higher-fidelity tool (Computational Fluid Dynamics, CFD) based on OpenFOAM is employed numerical computations. The validated against experimental measurements (decay tests forced surge motions) then applied to investigate whole floater each column at different amplitudes motions. decay match well with measurements, whereas CFD simulations underestimate decay. However, better agreement obtained between measured numerically estimated force oscillations surge. Furthermore, added derived from simulation 12% larger than that by potential flow theory, except under largest motion (up 35% larger). additional due viscous effects. shows small dependence oscillation period amplitude within tested range. At these frequencies, radiation completely negligible compared vortex shedding, accuracy Morison's drag forces capturing sensitive coefficient. • Comparison low-frequency coefficients for turbine. results agree pitch, differ Compared flow, predicts Important both damping. Similar conclusions are found using either or oscillation.