Experiment research of low-speed oblique water-entry of truncated cone-shaped projectile
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摘要: 为研究截锥体头型弹丸在低速斜入水条件下,头部直径大小对入水空泡及弹道特性的影响,基于高速摄像方法,开展不同截锥体头型弹丸低速倾斜入水对比实验,得到了截锥体头弹丸头部直径大小对入水空泡、运动速度、俯仰角的影响规律。实验结果表明:截锥体头弹丸头部直径越大,尾部越早与空泡下壁面发生碰撞;头部直径大小对空泡深闭合时间几乎没有影响;弹丸空泡随头部直径增大而增大;头部直径过大或者过小均不利于入水稳定性;弹丸速度低于临界值时呈上升趋势,高于临界值时将呈现下降趋势。Abstract: In this work we conducted comparative experiments of different truncated cone-nosed projectiles entering water at low-speed and oblique inclination to investigate the influence of the size of the head diameter on water-entry cavity and ballistic characteristics using high-speed photography. We observed and recorded the effects of the size of the head diameter on the cavitational evolution, velocity and pitch angle of the truncated cone-nosed projectiles. The following results were achieved: the larger the truncated cone head projectile diameter, the earlier the tail collides with the low surface cavity; the size of the head diameter has little effect on the cavity deep closure moment; the cavity of projectile increases with the increase of the head diameter; an excessively large or small head diameter is not conducive to the stability of water entry; when the water entry velocity of the projectile is below the critical velocity, the velocity shows an upward trend, while when it is above the critical velocity, it will show a downward trend.
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Key words:
- truncated cone /
- cavity /
- ballistic characteristics /
- water entry stability
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表 1 弹丸模型的头部特征
Table 1. Head characteristics of projectile model
弹丸模型 头部直径/mm 侧面面积/mm2 前端面面积/mm2 模型 A 2 70.65 3.14 模型 B 3 62.80 7.07 模型 C 4 51.81 12.56 表 2 韦伯数We
Table 2. Weber number We
工况 We 模型 A 模型 B 模型 C 1 1.78 1.66 1.50 2 1.44 1.32 1.20 表 3 弗劳德数Fr
Table 3. Froude number Fr
工况 Fr 模型 A 模型 B 模型 C 1 9.76 10.20 10.70 2 8.74 9.13 9.58 -
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