Microgravity Segregation in Collisional Granular Shearing Flows
Microgravity Segregation in Collisional Granular Shearing Flows
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DOI：
10.1007/978-94-015-9498-1_9
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发表时间：
2000
期刊：
影响因子：
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通讯作者：
M. Louge;J. Jenkins;A. Reeves;Stephen C. Keast
中科院分区：
文献类型：
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作者：
M. Louge;J. Jenkins;A. Reeves;Stephen C. Keast
本文研究了微重力条件下颗粒的剪切流动，其中颗粒的尺寸或质量的分离是由颗粒波动能量的空间梯度驱动的，实验是在NASA的微重力飞行器上进行的，飞行器上有一个形状像跑道的剪切单元，包含两种类型的球形颗粒的混合物。波动能量的梯度之间产生的内部，充满活力的移动边界驱动颗粒之间的碰撞和外部，更多的耗散边界的细胞的周边。通过在两个边界上覆盖适当尺寸和间距的凸起，并通过设置观察流动的平坦侧壁之间的距离，实现了能量学。通过高速摄像机捕获晶粒偏析和相应的速度统计数据，并使用计算机视觉软件进行分析。粒子的平均速度和波动速度与整个实验装置的计算机模拟结果进行了比较。
This article concerns granular shearing flows in microgravity where segregation of grains by size or mass is driven by spatial gradients in the fluctuation energy of the grains.Experiments were conducted on NASA’s microgravity aircraft with a shear cell shaped like a race track and containing a mixture of two types of spherical grains. A gradient of fluctuation energy was produced between the inner, energetic moving boundary driving collisions among the grains and the outer, more dissipative boundary at the periphery of the cell. The energetics were achieved by covering the two boundaries with bumps of appropriate size and spacing and by setting the distance between the flat side walls through which the flow was observed.The grain segregation and the corresponding velocity statistics were captured by a high-speed video camera and analyzed using computer vision software. The resulting profiles of particle mean and fluctuation velocities were compared with computer simulations of the entire experimental apparatus.