## 4 Conclusions  
In the present work, the random fluctuating wind with typhoon characteristics is simulated by coupling the measured data of the typhoon and inverse Fourier transformation. Based on the beam theory, a 6 MW wind turbine model is constructed to study its aeroelastic response in typhoon conditions. The aerodynamic loads and aeroelastic responses are calculated using the GH-Bladed software. A new method for calculating the dynamic responses of wind turbines under typhoon is established. The characteristics of the typhoon and the response of wind turbine at different yaw angles are analyzed. The conclusions are as follows:  
1. By analyzing the power spectrum and turbulence intensity of the simulated typhoon, it is found that the characteristics are similar to the measured results. Therefore, it can be considered that the simulated wind can represent the real-time fluctuating typhoon wind and establish the calculating reliability of the wind turbine response.
2. The typhoon is simulated based on the measured spectrum and its energy mainly concentrates in the low frequency region, which is close to the natural frequency of wind turbines and it is easy to resonate with the structural coupling. There are more abrupt changes in the higher order instantaneous frequency, which reflects the non-stationary characteristics of typhoons.
3. There are significant differences in the response characteristics of wind turbines at different yaw inflow angles. Especially when the inflow angle is 30 degrees, the blade exhibits the greatest load and shows the most violent vibration; when the yaw angle is 120 degrees, the extreme load of the tower exceeds the design ultimate value obtained according to the specification. The vibration energy of the tower is much higher than that of the other working conditions when the yaw angle is 30 degrees and 120 degrees. The simulation analysis of different sizes of wind turbine models  
Figure 11: Comparison of the instantaneous frequencies. (**a**) simulation by Kaimal spectrum; (**b**) simulation by [PERSON] spectrum; (**c**) simulation by measured spectrum.  
shows that the vibration changes similarly under different inflow yaw angles, which indicates the universality of the influence of inflow yaw angles on the aeroelastic responses of wind turbines.  
In this paper, the dynamic response of wind turbines in the eyewall region of typhoon is studied with the measured data. In the future, the fluctuating wind of typhoons with different wind levels and different distances from the wind eye will be simulated systematically, and the vibration characteristics and flutter instability of wind turbines in extreme weather conditions will be studied in detail. The Weather Research and Forecasting Model (WRF) for typhoon simulation and nonlinear methods for aeroelastic analysis should be taken into account for the accuracy improvements.  
[PERSON] was responsible for simulations and paper writing, [PERSON] and [PERSON] checked the measured data and advised simulation methods, [PERSON] and [PERSON] helped analyze results.  
This work was funded by the National Nature Science Foundation (Grant No. 51506089) and the Priority Academic Program Development of Jiangsu Higher Education Institutions.  
The authors declare no conflict of interest.