Effects of yawed inflow on the dynamic performance of suction caisson-supported offshore wind turbines via wind tunnel tests

Yawed inflow commonly occurs during the operation of offshore wind turbines, while its influence on the dynamic behavior of suction caisson-supported wind turbines remains insufficiently studied. In this study, a series of wind tunnel tests were conducted to investigate the effect of yawed inflow on the dynamic responses of a suction caisson-supported wind turbine under yaw angles of 0°, 15°, 30°, and 45°. The results show that yaw amplifies the structural dynamic responses, with the mean displacement, displacement fluctuations, and acceleration fluctuations increasing with yaw angle. Yaw also reduces the natural frequency and total damping ratio of the system. When yaw is taken into account, the variation range of the prototype natural frequency increases further, and the minimum natural frequency lies closer to the safety boundary of the 1P resonance region, thereby reducing the frequency safety margin. Furthermore, earth pressure measurements indicate that yaw significantly affects the soil–structure interaction of the suction caisson, inducing a systematic migration of the rotation center and enhancing the lateral earth pressure response. These findings highlight the necessity of explicitly accounting for yaw effects in the dynamic assessment and frequency design of suction caisson-supported wind turbines under operational conditions.