The Influence Of Rotor Spacing And Wall Effect On Aerodynamic Characteristics Of Quadcopter

Bridge wall detection with quadrotor UAV(Unmanned Aerial Vehicle)is the latest,most efficient and most flexible way to detect.The clarity of the image is critical to the results of the bridge inspection,this requires good stability when the quadrotor is on mission.The stability of the quadrotor is closely related to the aerodynamic interference between the rotors and the interference of external physical conditions.To ensure the flight stability of the quadrotor,In this paper,the aerodynamic interference between the rotors in the hover state and the influence of the aerodynamic characteristics of the bridge wall face the drone are investigated by the method of numerical simulation.Mainly reflected in the following three aspects:(1)Establish a pneumatic simulation model and use experiments to verify the effectiveness of simulation.According to the characteristics of low Reynolds environment flight of sUAV(small UAV),a pneumatic simulation model is established and the rotor lift measurement platform is built autonomously.By comparison,the laminar model has a better effect on the aerodynamic simulation of sUAV under low Reynolds.The simulation results are compared with the actual,with an error of 8.14%,which verifies the validity of the simulation model.(2)Exploring the effect of rotor spacing on the aerodynamic interference of quadrotor.Simulating the aerodynamic characteristics of sUAV with a rotor spacing of 2.2R to 5.0R,and exploring the variation of rotor spacing and the load characteristics of the sUAV,as well as the law of the fluctuation of lift force and torque.The simulation data are analyzed,and the results show that the aerodynamic interference before the rotor is not conducive to the improvement of the load characteristics of the aircraft and the flight stability.Interference between the wingtip vortex is the main cause of fluctuations in lift force and torque.The smaller the rotor spacing,the more severe the lift and torque fluctuations.The interference of the wake vortex mainly affects the mean size of lift and torque,the rotor spacing is the most serious when the rotor spacing is 3.0R,and the aerodynamic interference between the rotors basically disappears when the rotor spacing is 3.8R,which is the best way to lay out the rotor.(3)Exploring the effect of walls on the aerodynamic characteristics of quadrotor.The aerodynamic characteristics of the quadrotor with a wall spacing of 1.2R to 2.6R were calculated,and the change law of the rotor lift under different wall spacing conditions was studied.The results show that when flying near the wall,the wall only has pneumatic interference to the rotor near the wall,and the closer it is to the wall,the more severe the rotor lift fluctuation and the loss of lift force.The fluctuation of rotor lift is mainly due to the decrease of the strength of the high pressure area under the surface of the rotor during the flight of the rotor near the wall.At the same time,there is no change in the strength of the low pressure area on the top surface of the rotor;The best working distance for near-wall flight is 1.6R.