Unsteady aerodynamic characteristics of ducted coaxial propeller unmanned aerial vehicle

Based on the sliding grid technique and the SST(shear stress transport)k -ω turbulence model, a CFD(computational fluid dynamics) numerical method for the flow field of ducted coaxial propeller UAV(unmanned aerial vehicle) was established, and its effectiveness was verified by wind tunnel experiment results. The dynamic flow field of the ducted coaxial propeller UAV was numerically simulated. The influences of the factors such as duct, flight velocity, propeller speed and angle of attack on the unsteady aerodynamic characteristics of the ducted coaxial propeller UAV were analyzed. The calculation results show that the established CFD numerical method is suitable for simulating the dynamic flow field of ducted coaxial propeller UAV. The existence of duct significantly weakens the tip vortex, trailing edge vortex, propeller wake contraction, blade-vortex interaction and vortex-vortex interaction, and reduces the required power of the ducted coaxial propeller UAV. The lift and drag of the ducted coaxial propeller UAV increase as the forward velocity increases. The lift of the ducted coaxial propeller UAV increases and the drag decreases as the propeller speed increases. The drag of the ducted coaxial propeller UAV increases and the lift increases first and then decreases as the angle of attack increases.