弹带对高速旋转弹丸气动特性影响的数值模拟

为了研究弹带对高速旋转弹丸气动特性的影响，采用2阶Roe差分格式求解三维Navier-Stokes方程，湍流模型为SST k-ω模型。采用滑移网格技术处理弹体旋转引起的运动边界。以文献［6］进行风洞实验的155 mm无弹带弹丸为算例，数值计算结果与风洞实验数据吻合良好。分别对含弹带与无弹带弹丸在不同来流马赫数与攻角条件下的绕流场开展数值模拟，得到二者流场结构图谱及气动特性差异。分析结果表明：两种弹丸计算模型在弹带之前的压力分布基本一致，但弹带将诱导弹丸气动阻力面积增大，阻力系数有一定程度的升高，而且在弹带之后二者的压力分布差异较大；弹带因素对旋转弹丸气动特性的影响不可忽略。

Numerical Investigation on the Effect of Rotating Band on Aerodynamic Characteristics of High-speed Spinning Projectile

To investigate the effect of rotating band on the aerodynamic characteristics of high-speed spinning projectile, the second-order Roe-type upwind scheme and SST k-ω turbulence model are used to solve the three-dimensional Navier-Stokes equations. Moving boundary caused by the spinning of projectile is processed using sliding mesh method. The aerodynamic characteristics of 155 mm spinning projectile without rotating band are calculated, and the numerical results are in good agreement with the wind tunnel test data presented in Ref. 6 ]. The flow fields over high-speed spinning projectiles with and without rotating band are simualted under the conditions of different Mach numbers and angles of attack. By analyzing the differences of flow-field structures and aerodynamic characteristics, the conclusions are drawn as follows : the pressure distributions of two projectile models in front of rotating band are basically identical, but the rotating band structure increases the aerodynamic resistance area of the projectile, thus leading to the increase in resistance coefficient, and there is a great difference between the pressure distributions of the two spinning projectiles in the rear of the rotating band. This proves that the impact of the rotating band structure on the aerodynamic characteristics of spinning projectile cannot be neglected.