船尾外形对超声速弹丸减阻特性的影响研究

Research on Drag Reduction from Boat Tail of Supersonic Projectile

为了研究船尾外形对超声速弹丸底部阻力的影响特性及机理,采用基于N-S方程组和Spalart-Allmaras湍流模型的数值模拟方法,对某弹径为122 mm、7种不同船尾角度的旋成体超声速弹丸进行了不同马赫数和不同攻角下的数值模拟。比较分析了零攻角时船尾角度对弹丸底部流场气动特性的影响规律,得到了7°船尾角外形为该型弹丸的最佳船尾角外形。计算分析了不同马赫数下的减阻效率和小攻角条件下船尾弹丸底部流场的气动特性。计算结果表明:随着马赫数增加,减阻效率降低;随着攻角增大时,弹丸底部阻力系数、升力系数、全弹阻力系数、升阻比增大。

In order to study the characteristics and mechanism of the influence of boat tail on the base drag of the supersonic projectile,by the numerical method,aiming at the N-S equations and adopting the Spalart-Allmaras(S-A)turbulence model,the 122 mm spinning projectile with different boat tail angles was simulated under the condition that the inflow is a standard atmospheric pressure.The pressure,density,velocity and other parameters of the flow field of the projectile at the tail and base were obtained,and the pressure of the projectile was obtained by using the surface integral.The results show that 7°is the best boat tail angle of the projectile.The aerodynamic characteristics of the bottom flow field of the stern projectile were calculated and analyzed under the condition of drag reduction efficiency and small angle of attack under different Mach numbers.The results show that the drag reduction efficiency decreases with the increase of Mach number,and the base drag coefficient,lift coefficient,total drag coefficient and lift-drag ratio increase with the increase of attack angle.