非零攻角和侧滑角条件下弹托不同步飞离的数值模拟

对弹药在不同条件下的发射过程进行研究是研制弹药的重要一环，它有助于弹药适应现代战场复杂多变的发射环境。为了提高尾翼稳定脱壳穿甲弹(APFSDS)的射击精度和飞行稳定性，通过非结构化动网格技术和用户自定义函数耦合计算流体力学和六自由度外弹道程序，对非零攻角和侧滑角条件下APFSDS弹托相对弹体动态分离过程进行了数值模拟，获得了非零攻角和侧滑角条件下弹托分离流场、六自由度运动参数以及弹体气动参数的变化情况。结果表明：在非对称来流的影响下，弹托分离流场呈现非对称性，引起弹托受力不均匀，从而导致弹托非对称、不同步地飞离弹体，加大弹体受到的扰动,最终降低弹丸的射击精度和飞行稳定性。

Numerical Simulation on the Unsynchronized Discarding of Sabots at Non-zero Angles of Attack and Sideslip

The investigation on the dynamics process of launch of ammunition under different conditions is important for improving its performance during design and contributes to adapt the complex variable modern battlefield for the ammunition. For the purpose of improving the firing accuracy and flight stability of an armour-piercing fin-stabilized discarding sabot, the sabot dynamic discarding behavior after the projectile being ejected from the muzzle at non-zero angles of attack and sideslip is simulated by coupling the computational fluid dynamics and the six degree of freedom exterior ballistic code through the unstructured dynamic mesh technique and user defined function. The flow field characteristics and the trajectory parameters of all sabots are obtained. In addition, the aerodynamic coefficients of projectile are also obtained. The numerical results show that the asymmetric flow field of the sabots can be observed under the influence of the asymmetric inflow. This will lead to the nonuniform distribution of pressure on the sabot surfaces. The different trajectories of three sabots appear due to the unsynchronized and asymmetrical discarding of sabot. The increased aerodynamic interference between projectile and sabot reduces the firing accuracy and flight stability of projectile.