旋转弹丸入水侵彻规律

为了建立高速弹体入水弹道的模型，利用数字式高速录像机实验研究了球形与普通手枪两种弹丸在三个入水角、六种发射速度下斜入水的水中弹道轨迹与空泡。实验结果表明，弹丸形状对入水弹道的稳定性有重要影响。球形弹丸在斜入水时弹道稳定性较好，而普通制式弹丸的弹道不稳定。在一定的入水角与速度范围内，球形弹丸入水初期弹道的空泡特性、弹道轨迹以及速度衰减规律具有一定的相似性。而对于水中速度随时间的衰减规律，则两种弹丸都具有一定的相似性，且表现出极强的速度衰减特性。给出了弹丸水中速度衰减规律的数学预报模型，并与实验结果进行了比较，理论结果与实验结果吻合较好。

Experimental study on the penetration law for a rotating pellet entering water

To create a mathematical model for the hydro-ballistic trajectory of high speed pellet entering water, the hydro-ballistic trajectory and cavity of sphere and pistol pellets entering water at three oblique angles and six velocities have been experimentally studied using a high-speed digital video recorder. The experimental results show that the shape of the pellet has significent influence on the hydro-trajectory stability. The hydro-ballistic trajectory of the sphere pellet obliquely entering water is more stable than that of the general pistol pellet. The initial cavity, ballistic trajectory and velocity attenuation of the sphere pellets are similar at different water-entry angles and initial velocities. The velocity of pellet in water decreases very quickly, and the attenuation is similar for both of the sphere and pistol pellets. A calculation model is proposed to predict the velocity attenuation of the pellet. Calculated results are in good agreement with the experimental.