In this study, we investigated the water entry trajectory characteristics of a projectile with an asymmetric nose shape at different initial impact velocities and impact angles experimentally. With high speed photography, the water entry cavities and projectile motions were captured to obtain the trajectory curve and the attitude angle of the projectile. Compared to the projectile with a flat nose shape, the experimental results presented that the trajectory of the projectiles with asymmetrical nose shapes shows obvious deflection during the water entry process, and the deflection amplitude of the trajectory increases as the cut angle decreases under the same water entry conditions. It is found that the change trend of the projectile’s attitude angle is the almost same under different impact angle conditions. In addition, for the same type of asymmetric nose shape, the trajectory deflection increases with the increase in impact velocity. Finally, a theoretical model of the water entry trajectory was established to predict the projectile motion and trajectory of the projectile with an asymmetric nose shape before the tail-slap process. We compared the experimental data with the calculated results, and the theoretical calculation gave a good approximation with the experimental results. The maximum error of the displacements between the theoretical results and the experimental results is only 3.25%.

中文翻译：

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鼻形不对称弹丸入水轨迹的实验研究

在这项研究中，我们通过实验研究了不对称鼻形弹丸在不同初始冲击速度和冲击角度下的入水轨迹特性。通过高速摄影，捕获了入水腔和弹丸运动，以获得弹丸的轨迹曲线和姿态角。实验结果表明，与鼻尖形状为扁平形的弹丸相比，鼻形不对称的弹丸在入水过程中存在明显的挠度，并且在相同水位下，弹丸的偏转幅度随着切角的减小而增大。进入条件。发现在不同的冲击角条件下，弹丸姿态角的变化趋势几乎相同。此外，对于相同类型的不对称机头形状，轨迹偏转随冲击速度的增加而增加。最后，建立了入水轨迹的理论模型，以预测在拍尾过程前鼻梁形状不对称的弹丸运动和弹道。我们将实验数据与计算结果进行了比较，理论计算结果与实验结果具有很好的近似性。理论结果与实验结果之间位移的最大误差仅为3.25％。建立了入水轨迹的理论模型，以预测尾巴拍击前鼻翼形状不对称的弹丸运动和弹道。我们将实验数据与计算结果进行了比较，理论计算结果与实验结果具有很好的近似性。理论结果与实验结果之间位移的最大误差仅为3.25％。建立了入水轨迹的理论模型，以预测尾巴拍击前鼻翼形状不对称的弹丸运动和弹道。我们将实验数据与计算结果进行了比较，理论计算结果与实验结果具有很好的近似性。理论结果与实验结果之间位移的最大误差仅为3.25％。