Calculation And Research On Aerodynamic Characteristics Of Missile During Low Spinning Speeds

The spinning missile,which has many advantages such as reducing the manufacturing error,simplifying the control system and generating the gyro stabilization effect,is widely used in the fields of artillery,rockets and short-range tactical missiles.However,compared with the non-spinning missile,owing to the rotation effects,the aerodynamic characteristics of the spinning missile are more complicated and the undesired effects such as Magnus effect,conical motion,and resonance coupling are introduced.All these undesired effects are intimately associated with the variations of the aerodynamic parameters.Thus,this paper systematically studies the aerodynamic characteristics of the spinning missile,which contributes to the design of the spinning missile.First of all,the domestic and international research status and methods about the spinning missile's aerodynamic characteristics are explained in detail,especially sliding mesh technology.The numerical simulation of the ANF and the F4 missile are carried out to study the aerodynamic characteristics.The obtained numerical simulation results are compared with the corresponding experimental results of the wind tunnel,verifying the reliability of the research method adopted in this paper.Secondly,in order to study the effects of the low-speed rotation on the aerodynamic characteristics of flat-headed tail missile,a numerical calculation model of a wing-body combined missile is established and a structured computational mesh of the complex missile model is generated.The sliding mesh technology is used to realize the rotation of the missile.We use the fluent dymnamic software to study the,and also investigate the possible influences of different rotating speeds(0.5r/s,1 r/s,2 r/s),Mach numbers(0.9,1.1,1.4,1.6,2,0),angle of attack(2°,4 °),roll angle(varying from 0° to 360°)on the aerodynamic parameters.The returned results show that the longitudinal aerodynamic parameters of the missile do not change with the increase of the rotating speed.Therefore,the longitudinal aerodynamic parameters of the rotating missile can be solved by the steady theory.The average rolling moment coefficient shows a linear trend with the increase of the rotating speed.The Magnus effect increases significantly with the increase of the rotating speed and this observation can be explained though the structure of the flow field.At the same time,it is found that all aerodynamic coefficients change periodically with the roll angle.Then,to study the influence of the oblique angle of wing on the aerodynamic characteristics of the missile in the rotating state,three numerical models of a wing-body combined missile with different oblique angle of wing are established.The same numerical simulation method is used to simulate the aerodynamic characteristics of the three types of missiles under different conditions,The effects of the oblique angle of wing(0°,1 °,2 °)on the aerodynamic parameters were analyzed.The numerical results show that with the increase of the oblique angle of wing,the lift-drag ratio of the rotating missile obviously decreases;the Magnus effect increases significantly and the average rolling moment coefficient vary linearly.According to the relationship between the average rolling moment coefficient and the rotating speed and the oblique angle of wing,a new method for calculating the average roll moment coefficient and the balancing rotating speed is proposed and validated.Finally,the aerodynamic characteristics of missile with wrap-Around Fins at low-speed rotation are studied,and of particular interest is the influence of the rotating speed(0r/s,0.5r/s,1r/s)on its rolling characteristics and Magnus effect.The 2-roll-change phenomenon is explained by the pressure cloud map of the wing with the Mach number changes.