High-Fidelity Aeroelastic Analysis of a Wind Turbine Using a Nonlinear Frequency-Domain Solution Method

This paper investigates the aeroelastic behaviour of a full wind turbine model with realistic blade vibration amplitude (9% span) using a nonlinear frequency-domain solution method. The primary objective is to demonstrate the computational efficiency of this method for an aeroelastic analysis compared to resource-intensive time-domain approaches. The underlying CFD model was validated against experimental data and benchmark simulations. The frequency-domain method was then validated against a conventional time-domain method, comparing aerodynamic damping and unsteady pressure distributions, with strong agreement observed. Results show a more complex unsteady pressure distribution at 324.5 RPM compared to 424.5 RPM, directly affecting aerodynamic damping. While aeroelastic stability was observed at both speeds, aerodynamic damping was significantly lower at 324.5 RPM. Flow field analysis reveals a clear relationship between relative velocity, static pressure, and blade vibration. Critically, the frequency-domain method achieved comparable accuracy to the time-domain method but with a significantly reduced computational cost (9 h versus 120 h), making it highly attractive for routine aeroelastic analyses and design optimisation.