小攻角下船尾外形对旋转弹丸马格努斯效应影响的数值研究

Influence of Boattail on the Magnus Effect of Spinning Non-finned Projectile at Small Angles of Attack

为了研究小攻角下船尾外形对旋转弹丸马格努斯效应的影响,对不同船尾外形的旋转弹丸进行了数值模拟,得到了气动力及力矩随马赫数Ma、船尾角θ_t和船尾长度L_t与弹径D的比值L_t/D的变化。根据气动特性及流场结构,分析了船尾及马赫数对旋转弹丸马格努斯效应的影响,并研究了旋转弹丸马格努斯效应的产生机理。结果表明:在船尾段,由边界层位移厚度的非对称畸变所产生的沿z轴负方向的力随θ_t和L_t/D的增大而逐渐增大;由周向切应力非对称畸变所产生的沿z轴正方向的力沿x轴逐渐增大,随Ma的增大而逐渐增大,随θ_t和L_t/D的增大而逐渐减小;由沿弹体轴向和周向压力分布的非对称性所产生的沿z轴负方向的力随θ_t和L_t/D的增大而逐渐增大,并且在超声速时随Ma的增大而逐渐减小,在亚跨声速时随Ma的增大而逐渐增大。

In order to study the influence of boattail on the Magnus effect of spinning projectile at small angles of attack,the configurations with various boattail angles（ θ_t） and lengths（ L_t/D） are numerically simulated. The variations of the aerodynamic force and moment with Ma,θ_tand L_t/D are obtained. According to the aerodynamic characteristics and flow field structure,the effects of boattail on Magnus effect are studied in details,and the mechanism of the Magnus effect for spinning projectile is analyzed. The results show that component of Magnus force along-z direction increases with θ_tand L_t/D due to the asymmetric distortion of the boundary layer. Meanwhile,the force along z-direction due to the asymmetric circumferential shear stress distortion decreases gradually with θ_tand L_t/D,while increasing with Ma.The force along-z direction due to the asymmetric distortion of axial and circumferential pressures increases with θ_t,L_t/D,and Ma for Ma≥1,while decreasing with Ma for Ma 1.