初始扰动对射弹尾拍运动及弹道特性影响分析

Analysis of tail-slapping and ballistic characteristics of supercavitating projectiles under different initial disturbances

摘要:

为研究射弹的初始扰动对射弹的尾拍运动、超空泡形态及弹道特性的影响，基于计算流体动力学程序CFX，通过二次开发使用CEL语言将刚体动力学方程嵌入计算模块并实现刚体动力学方程与流体(unsteady reynolds averaged navier-stokes,URANS)方程的耦合求解，建立了超空泡射弹在不同初始扰动下自由减速运动的计算流体动力学模型.在相同的初始速度下，计算并对比分析射弹在不同初始扰动下的空泡形态特征、弹尾压力分布特征及弹道特性.计算结果表明：射弹发生尾拍运动时弹体尾部与空泡壁面发生碰撞，这种碰撞破坏了空泡形态的对称性；初始扰动对射弹的水平速度与位移影响较小，但对垂直位移影响较大；初始扰动越大，射弹的俯仰角、角速度和角加速度的振幅越大且频率越高.

Abstract:

In order to investigate the influence of initial disturbances on the cavity profile, tail-slapping and ballistic characteristics, the computational fluid dynamics(CFD) model that can be used to solve the coupling equations of rigid body dynamics and unsteady reynolds averaged navier-stokes (URANS) of fluid under different initial disturbances is established based on the CFD program CFX and its expression language CEL. The cavity profile pressure distribution of the projectile tail and ballistic characteristic when the tail-slapping occurs are studied using this model. The result shows that the tail-slapping of the projectile destroys the symmetry of cavity profile; the initial disturbances have slight influences on the velocity and displacements in x-direction but have obvious influences on the vertical displacements; the amplitudes and frequencies of the pitch angle, angular velocity and angular acceleration increase with the increase of the initial disturbances.