Numerical Simulation And Flow Analysis Of Flow Around Control Surface Of A Flying Wing UAV

UAV(Unmanned Aerial Vehicle)have been widely used due to its high safety factor,high mobility,low cost,simple structure and other characteristics in the military and civilian areas.With the development of computer technology and electronic driving fly control technology,tailless flying wing layout has been gradually applied in the UAV design due to its high resistance ratio,excellent stealth performance.This paper introduces a small aspect ratio tailless flying wing layout UAV and use the numerical simulation method to analyze the aerodynamic performance of the UAV under low speed.The main research work are as follows:(1)This paper investigates a variety of tailless flying wing layout UAV and summed up the advantages of tailless flying wing layout compared to other layout and urgent problems to be solved.(2)Using the current widely used turbulence model to simulate the two-dimensional wing,three-dimensional wing and wing-body model from low speed to transonic velocity.Comparing with the wind tunnel data,the simulation results show that the SST k-w turbulence model can simulate the flow phenomena of different sonic velocity well.(3)This paper introduces a small aspect ratio flying wing UAV,and the aerodynamic parameters such as lift coefficient,drag coefficient and pitch moment coefficient of the UAV are calculated by commercial CFD software.Using pressure distribution contour and the distribution of the pressure coefficient of the wing surface along the wing in different stations to verify the high aerodynamic efficiency of the flying wing layout.Then calculating the aerodynamic derivatives of the UAV in longitudinal and horizontal direction and the manipulation efficiency of different rudder surfaces,and analyzing the stability and control ability of the longitudinal and horizontal direction.(4)For the yaw control,the aerodynamic parameters of the spoiler slot deflector(SSD)and elevon are calculated.It is concluded that the SSD has a strong coupling roll moment.The elevon are not suitable for yaw control.When the SSD is opened and controlling the elevon,the contribution of the roll moment,the pitching moment and the lift is opposite.The combined control surfaces has a strong ability for yaw control.At last,this paper reveals the physical mechanism of the combined control surfaces.