Impact jetting by a solid sphere
Impact jetting by a solid sphere
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DOI：
10.1017/s0022112003007274
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发表时间：
2004-01
影响因子：
3.7
通讯作者：
S. Thoroddsen;T. Etoh;K. Takehara;Y. Takano
中科院分区：
文献类型：
--
作者：
S. Thoroddsen;T. Etoh;K. Takehara;Y. Takano
我们使用一种新型的超高速摄像机来研究固体球体撞击液体表面的初始阶段，发现在初始接触之后立即出现的高速水平射流。当Re> 2 × 10^4$时，当球体和液体之间的水平接触仅为其直径的12%时，射流出现。对于最大的雷诺数，该射流可以以超过球体冲击速度的30倍的速度行进。这种喷射发生得更快，而且比以前观察到的标准化速度高得多。射流分裂成液滴喷雾有时通过在液体层中形成袋而发生。在撞击的早期，传递到射流和随后的喷射片的能量估计远大于与液体池内的附加质量相关的能量。因此，喷射将大大增加球体上的初始冲击力。
We use a novel ultra-high-speed video camera to study the initial stage of the impact of a solid sphere onto a liquid surface, finding a high-speed horizontal jet which emerges immediately following the intial contact. For ${\hbox{\it Re}} > 2 \times 10^4$ the jet emerges when the horizontal contact between the sphere and the liquid is only 12% of its diameter. For the largest Reynolds numbers this jet can travel at more than 30 times the impact velocity of the sphere. This jetting occurs sooner and at much higher normalized velocities than has been observed previously. The breakup of the jet into a spray of droplets sometimes occurs through formation of pockets in the liquid sheet. Early in the impact, the energy transferred to the jet and the subsequent spray sheet is estimated to be much larger than the energy associated with the added mass inside the liquid pool. The jetting will therefore greatly increase the initial impact force on the sphere.