Khosropour R, Valachovic E, Lincoln B
Physics Department, Union College, Schenectady, New York 12308, USA.
Phys Rev E Stat Phys Plasmas Fluids Relat Interdiscip Topics. 2000 Jul;62(1 Pt B):807-12. doi: 10.1103/physreve.62.807.
In a horizontally rotating cylinder, size segregation, pattern formation, and its time development are studied for a binary mixture of rodlike and disklike materials at various rotational frequencies. The rodlike particles formed a network that influenced their mobility and the shape of the avalanching surface. Windows installed on the cylinder enabled us to examine and control the distribution of the components of the mixture throughout the bulk. This has allowed us to study the evolution of naturally occurring and artificially created patterns. All observed patterns had a degree of asymmetry and were unstable. The stability of a band pattern is shown to depend on its symmetry. Qualitatively, the time for the transition from one set of bands to another was inversely related to the degree of asymmetry of the pattern. In addition, we propose that the parameter D/d (diameter of the cylinder over the diameter of the grains) plays a significant role in the functional dependence of the avalanching surface current on the dynamical angle of repose, and in the segregation process itself.
在一个水平旋转的圆筒中，研究了在不同旋转频率下棒状和盘状材料的二元混合物的尺寸分离、图案形成及其随时间的演变。棒状颗粒形成了一个网络，该网络影响了它们的流动性以及崩塌表面的形状。安装在圆筒上的窗口使我们能够检查和控制混合物各组分在整个体积中的分布。这使我们能够研究自然形成和人工创造的图案的演变。所有观察到的图案都有一定程度的不对称性且不稳定。带状图案的稳定性被证明取决于其对称性。定性地说，从一组带过渡到另一组带的时间与图案的不对称程度成反比。此外，我们提出参数D/d（圆筒直径与颗粒直径之比）在崩塌表面电流对动态休止角的函数依赖关系以及分离过程本身中起着重要作用。
