Numerical simulation study on the aerodynamic parameters of a wind turbine under surge motions

In diverse environmental loads, the along-wind load of a wind turbine plays a dominant role. This study employs the unsteady Reynolds-averaged Navier–Stokes (URANS) method to perform numerical simulations of the unsteady aerodynamic characteristics of a full-scale NREL 5 MW horizontal-axis wind turbine under different intensities of harmonic surge motion . Additionally, the identification and parameterization of aerodynamic parameters of the rotor are carried out. The results show that the variation patterns of the unsteady aerodynamic characteristics are closely linked to changes in the surge motion velocity, with significant coupling observed between the flow field variations and structural motion. The aerodynamic damping ratios are positive in all cases in this study. A positive correlation is found between the rotor aerodynamic damping ratio, the reduced inflow wind speed , and the tip speed ratio. As the amplitude of the surge motion increases, the aerodynamic damping ratio tends to decrease, although the overall change is relatively small. The aerodynamic stiffness is significantly influenced by the tip speed ratio and surge amplitude, leading to varying degrees of frequency drift in the overall structure of the wind turbine. • The aerodynamics of FOWT under surge motions is analyzed with URANS and SDOF model. • Effects of surge frequencies and amplitudes are studied in time-frequency domain. • The dynamic inflow effect is revealed through transient flow field analysis. • Aerodynamic damping and stiffness are studied based on dimensionless parameters.