Stokes' cradle: normal three-body collisions between wetted particles
Stokes' cradle: normal three-body collisions between wetted particles
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DOI：
10.1017/s0022112009993715
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发表时间：
2009-12
影响因子：
3.7
通讯作者：
C. Donahue;C. Hrenya;Robert H. Davis;K. Nakagawa;A. P. Zelinskaya;G. Joseph
中科院分区：
文献类型：
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作者：
C. Donahue;C. Hrenya;Robert H. Davis;K. Nakagawa;A. P. Zelinskaya;G. Joseph
在这项工作中，实验和理论相结合的是用来研究固体颗粒与液体涂层（即“湿”颗粒）之间的三体法向碰撞。实验是使用斯托克斯摇篮进行的，斯托克斯摇篮是一种受牛顿摇篮桌面玩具启发的装置，除了湿颗粒。与以前的两体系统不同，在碰撞时可能会聚集或反弹，在三体系统中可能有四种结果：完全聚集，牛顿摇篮（撞击物和目标粒子撞击聚集），反向牛顿摇篮（目标聚集而撞击物分离）和完全分离。碰撞后的速度测量的参数范围内。对于所有实验，随着撞击速度的增加，观察到的结果的进展是完全聚集的，反向牛顿摆和完全分离的。值得注意的是，随着油的粘度增加，实验揭示了两组相邻颗粒的临界斯托克斯数（区分从附聚到分离的转变的斯托克斯数）的降低。基于润滑力、颗粒变形和弹性，提出了一种标度理论。与以前对两粒子系统的研究不同，在预测与实验一致的状态图时，发现两个物理学问题至关重要：（i）由于目标颗粒之间预先存在的液体桥，在目标颗粒反弹时的附加阻力（在两粒子碰撞中没有对应物），以及（ii）由于碰撞颗粒之间的高压下液体层的玻璃化转变而增加回弹标准。
In this work, a combination of experiments and theory is used to investigate three-body normal collisions between solid particles with a liquid coating (i.e. ‘wetted’ particles). Experiments are carried out using a Stokes' cradle, an apparatus inspired by the Newton's cradle desktop toy except with wetted particles. Unlike previous work on two-body systems, which may either agglomerate or rebound upon collision, four outcomes are possible in three-body systems: fully agglomerated, Newton's cradle (striker and target particle it strikes agglomerate), reverse Newton's cradle (targets agglomerate while striker separates) and fully separated. Post-collisional velocities are measured over a range of parameters. For all experiments, as the impact velocity increases, the progression of outcomes observed is fully agglomerated, reverse Newton's cradle and fully separated. Notably, as the viscosity of the oil increases, experiments reveal a decrease in the critical Stokes number (the Stokes number that demarcates a transition from agglomeration to separation) for both sets of adjacent particles. A scaling theory is developed based on lubrication forces and particle deformation and elasticity. Unlike previous work for two-particle systems, two pieces of physics are found to be critical in the prediction of a regime map that is consistent with experiments: (i) an additional resistance upon rebound of the target particles due to the pre-existing liquid bridge between them (which has no counterpart in two-particle collisions), and (ii) the addition of a rebound criterion due to glass transition of the liquid layer at high pressure between colliding particles.