The role of interstitial gas in determining the impact response of granular beds
The role of interstitial gas in determining the impact response of granular beds
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DOI：
10.1209/0295-5075/93/28008
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发表时间：
2010-12
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影响因子：
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通讯作者：
J. Royer;B. Conyers;E. Corwin;P. Eng;H. Jaeger
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文献类型：
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作者：
J. Royer;B. Conyers;E. Corwin;P. Eng;H. Jaeger
我们研究了固体球体对细粒颗粒床的影响。使用高速 X 射线照相术，我们跟踪球体的运动和床填充分数的局部变化。改变初始填充密度和环境气压，我们发现间隙气体对床的冲击响应的影响完全相反：气体和颗粒之间的动态耦合允许在最初松散的床中更容易渗透，但在更密集的填充床中阻碍渗透。局部填充密度的高速成像表明，这些看似不协调的效应有一个共同的根源：对间隙空气引起的床填充变化的阻力。
We examine the impact of a solid sphere into a fine-grained granular bed. Using high-speed X-ray radiography we track both the motion of the sphere and local changes in the bed packing fraction. Varying the initial packing density as well as the ambient gas pressure, we find a complete reversal in the effect of interstitial gas on the impact response of the bed: The dynamic coupling between gas and grains allows for easier penetration in initially loose beds but impedes penetration in more densely packed beds. High-speed imaging of the local packing density shows that these seemingly incongruous effects have a common origin in the resistance to bed packing changes caused by interstitial air.