Abstract: The wind resistance of coaxial rotors in hover is tested considering the horizontal and vertical light breezes with the wind velocity varied from 1.6 to 3.3 m/s and the gentle breeze with the wind velocity varied from 3.4 to 5.4 m/s in the natural environment. A velocity distribution model of blade in the natural incoming flow is established, and a low-speed wind tunnel is also introduced to simulate the natural disturbance on the coaxial rotors. The sliding mesh method is adopted to calculate the flow field and capture the aerodynamic interference in the natural incoming flow, mainly including the distribution of tip pressure, the streamline distribution of flow field and the velocity vector of blade tip. Results show that the proposed simulation method can accurately reflect the influence of natural incoming flow on the aerodynamic characteristics of coaxial rotors. Compared to the case with no wind gust, the performance of coaxial rotors is declined due to vertical incoming flow. It is noted that the coaxial rotors can effectively resist the wind disturbance in the horizontal incoming flow, and eventually the rotor performance is greatly improved with the increase in wind velocity.Key

Key words: coaxialrotor, naturalwindgust, aerodynamicinterference, windtunneltest, slidingmesh