Dynamic Performance of Wind Turbines Under Yaw Angles and Seismic Inputs: Insights From Combined Wind Tunnel and Shaking Table Tests

This study investigates the seismic response behaviour of wind turbines in operational conditions, highlighting how yaw misalignment and seismic input characteristics influence their dynamic performance. A novel wind tunnel-shaking table (WTST) test platform was developed to apply wind and seismic loads simultaneously. Using a 1:100 scale model wind turbine, tests were conducted with El-Centro and Taft seismic records obtained from the Pacific Earthquake Engineering Research (PEER) Strong Earthquake Database, which were adjusted in amplitude and time to simulate realistic earthquake conditions. Experiments involved four yaw conditions (yaw angle = 0°, 15°, 30° and 45°) and twelve different seismic input angles with three peak ground accelerations (PGAs) under operational conditions. The results reveal that yaw angles of a wind turbine significantly affect aerodynamic characteristics, thereby influencing seismic dynamic response. The study identifies the seismic incidence angle aligned with the turbine's yaw direction as the most critical scenario and finds that under operational conditions, seismic excitation dominates the structural response. As the yaw angle increases, nacelle displacement decreases, and acceleration rises under wind-only loading due to reduced aerodynamic damping. When wind turbines experience earthquakes during operation, displacement and acceleration responses exhibit symmetric double-peak patterns, with the peak positions shifting according to the yaw angle. The maximum displacement occurs when seismic and wind loads align with the yaw direction, while the highest acceleration arises when seismic loads oppose the wind direction. The nacelle, as the most vulnerable component, can experience acceleration amplification factors up to three, highlighting significant seismic energy concentration. These insights advance understanding of wind turbine behaviour under coupled wind and seismic excitations, offering valuable guidance for the design of resilient wind energy systems.