旋成体射弹倾斜入水运动仿真

为了研究运动参数和弹头外形对弹体斜入水过程的影响规律,采用气液两相流体积分数和水汽空化模型,通过嵌套网格实现刚体三自由度运动学和动力学耦合,模拟了弹体以80～100 m/s速度倾斜入水开空泡阶段的运动过程。经文献实验验证,入水弹体速度与位移的误差为0～6%和-8%～0,转动角度误差为-6%～0。通过对入水速度和入水角度的多工况模拟研究,发现入水速度增大,弹体轴向冲击载荷增大,最大载荷与速度的平方呈线性关系,弹体速度非线性衰减率大;入水角增大,弹体转动角速率减小,运动稳定性强,速度衰减率不受入水角影响。与圆锥头部弹体相比,采用头部阶梯状修型后的弹体的平均速度衰减率、转动角速率和最大轴向冲击载荷分别降低到66.7%、40%和77.2%,显著提高了运动稳定性。

Simulation of the oblique entry motion of convolutional projectile into water

In order to study the influence of motion parameters and warhead shape on the oblique entry process of a projectile into water, adopting volume of fraction of gas-liquid two-phase flow and water vapor cavitation model. The three-dimensional kinematics and dynamics of the rigid body were coupled by nested grids, and the motion process of the projectile in the stage of speed 80~100 m/s tilting into water and opening cavitation process was simulated. According to the literature experiments, the prediction errors of the velocity and displacement of the underwater projectile are 0~6% and -8%~0, and the rotation angle error is - 6%~0. Through the simulation study of the water entry velocity and angle of entering water under multiple working conditions, it is found that with the increase of the water entry velocity, the axial impact load of the projectile increases. The maximum load is linearly related to the square of the speed, and the nonlinear attenuation rate of the velocity is large. The larger the angle of entry, the smaller the angular rate of rotation of the projectile body, the stronger the stability of movement. But the velocity decay rate is not affected by the angle of entry.The projectile body adopted a stepped head modification, compared with the conical nose projectile, the average velocity decay rate, rotation angular rate and maximum axial impact load of the body after the head stepped modification are reduced to 66.7%, 40% and 77.2% respectively. The motion stabilitity is improved significantly.