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.