Study On Aerodynamic Characteristics Of Ducted Aircraft Based On Synthetic Jet Technology

Aiming at the maneuverability and stability of the current ducted fan drone,a ducted fan aircraft scheme based on synthetic jet technology is designed to control the flight attitude of the drone by controlling the flow field of the trailing edge of the drone by a synthetic jet actuator.The aircraft is mainly composed of a duct body,a fan,a jet actuator and so on,and the synthetic jet actuators of each group are controlled independently of each other.The synthetic jet actuator not only changes the yaw and pitch of the ducted fan aircraft,but also enables the aircraft to have fast response and high maneuverability.Firstly,the overall layout of the ducted fan drone is designed in this paper,and the 3D model of the ducted drone is established.And the detailed force analysis of the ducted drones laid the foundation for numerical calculation.Secondly,the aerodynamic characteristics of the isolated fan and the ducted fan aircraft during flight are numerically analyzed.There factors,the number of blades,the propeller speed and the inflow velocity,were considered to analyze the influence on the aerodynamic forces of the isolated fan;and the three factors of incoming flow speed,fan speed and ducted angle of attack are considered in the ducted fan to affect the aerodynamics of the aircraft;and the relationship between the ducted drone and the isolated fan is compared and analyzed,which lays the foundation for structural optimization and flow control of the ducted drone.Thirdly,combined with the analysis of the aerodynamic characteristics of isolated ducted ducts,and a synthetic jet exciter simulation model is established.And the jet technology is introduced into the isolated duct,wherein the jet contains a constant jet and a synthetic jet.Its aerodynamic characteristics are analyzed by the CFD method,and the influence of the steady jet and the synthetic jet on the isolated duct is compared and analyzed,which lays a foundation for the introduction of active flow control technology into ducted fan drones.Then,combined with the aerodynamic characteristics analysis of the ducted fan unmanned aerial vehicle body,the synthetic jet technology is introduced into the ducted fan,and the aerodynamic characteristic of the ducted fan are analyzed by CFD method,which takes into account the influence of constant jet and synthetic jet on the aerodynamic force and torque of the ducted fan.And the effects of the opening ofthe jet and the unopening of the jet on the aerodynamic characteristics are analyzed.Finally,the case of the ducted drone with crosswind interference during the forward flight was studied.The crosswind disturbance factors include the crosswind wind speed and the crosswind direction.The influence of crosswind interference on the aerodynamic characteristics of the ducted fan drone is considered.And under the influence of the jet on the wake of the ducted fan,the stability control effect of the synthetic jet on the ducted fan is verified under the influence of crosswind interference.In summary,the synthetic jet exciter is applied to the ducted fan drone,and the aerodynamic force and torque of the ducted fan are analyzed in detail,which provides a theoretical basis for structural design optimization and control system design in this paper.And the influence of crosswind interference on the stability of the ducted fan is analyzed.The synthetic jet exciter can properly balance the influence of crosswind interference on the ducted fan,and provide reference for the aerodynamic characteristics analysis of the ducted fan drone in the interference state and the aircraft dynamics modeling under the crosswind interference state.And provide data support for the stability analysis of the ducted aircraft in the interference state.