掠飞末敏弹滚转气动特性研究

Aerodynamic Characteristic Study Towards the Hedgehopping Terminal Sensitive Projectile at Rolling State

为研究掠飞末敏弹在高速滚转状态下的气动特性,对其进行了静态和自由滚转风洞实验研究,在此基础上,结合数值仿真和近似理论方法,分析了弹箭高速滚转运动对其气动参数的影响,并获得了不同马赫数下的平衡转速随尾翼结构参数的变化规律.结果表明:平衡转速随马赫数增加而增大,但变化斜率随马赫数增加有所减小;在相同马赫数下,平衡转速随攻角增加而减小,且变化规律具有非线性特性;增大尾翼根稍比、扭曲率以及后掠角均有利于提高弹箭平衡转速;弹箭在高速滚转状态下的气动特性与静止状态相比存在显著差异,除产生较大的偏航力矩外,还将导致俯仰力矩系数减小、压心位置前移等现象,这对提高尾翼弹箭飞行稳定性是不利的.

In order to investigate the aerodynamic characteristics of the hedgehopping projectile under the condition of high-speed rolling,comparative experimental investigations using wind tunnel tests were implemented first at static and freely rolling states.Based on this,both numerical technique and approximate analytical method were further employed to quantitatively analyze the influence of such a high-speed rolling state on aerodynamic parameters under various Mach numbers.Corresponding variation laws of the balance rotation speeds with respect to the empennage geometries were obtained as well.Main results indicate the following：the balance rotation speed rises with a descending gradient and an increasing Mach number;under a fixed Mach number,the increasing attack angle can lead to a non-linear decrease for balance rotation speed;all increasing root tip ratio,twist rate and sweepback enable a higher balance rotation speed;the aerodynamic characteristics in high-speed rolling states are distinctly different from those of the static case;besides the larger yawing moment,the lower pitching moment and the forward shift of pressure center are also caused,both of which are adverse to the flight stability of empennage projectile.