弹头外形对非零攻角亚音速旋转弹丸气动特性的影响

为寻求阻力特性受攻角影响较小的弹丸外形，提高射击精度，针对35 mm 口径亚音速旋转稳定弹丸，利用FLUENT 软件仿真研究半球形、抛物线形、截锥形三类弹头外形对非零攻角亚音速旋转弹丸气动特性的影响，并借助Matlab 软件模拟亚音速范围内弹丸阻力系数 Cx 随攻角 x 的变化规律，计算得到弹丸攻角系数 K 值在16～20；结果表明：半球形弹头外形对非零攻角亚音速旋转弹丸气动特性的影响较小，而抛物线形弹头外形对亚音速旋转弹丸阻力系数的影响较小；用于描述弹丸阻力系数 Cx 随攻角变化规律的函数 Cx ＝cx2＋dx ＋e 相对函数 Cx ＝ax2＋b 更为精确，相对误差前者小于1％，后者小于4．5％。

Influence of Projectile Shape on Aerodynamic Characteristics of Subsonic Grenade Having Attack Angle

In order to search the projectile shape where the attack angle has less impact on resistance characteristics,through which to improve shooting accuracy.Projectile shapes of hemispherical,parabolic and truncated cone were studied by using FLUENT on the basis of a kind of 35 mm caliber subsonic grenade.The variation of drag coefficients obtained and attack angle were fitted and simulated by using Matlab,and the attack angle coefficient is 16 ~20.The result shows that projectile shape of hemispherical has less impact on resistance characteristics of subsonic grenade having attack angle;The drag coefficients of projectile shape of parabolic are smaller;Function of Cx =cx2 +dx +e used to describe the drag coefficient Cx of projectile varying with attack angle is more accurate than the function of Cx =cx2 +dx +e, and the relative error of the former is less 1% and the latter is less 4.5%.