St. Anthony Falls Laboratory, Department of Civil Engineering, University of Minnesota, Minneapolis, Minnesota 55414, USA.
Phys Rev Lett. 2011 May 27;106(21):218301. doi: 10.1103/PhysRevLett.106.218301.
We computationally study shear-induced segregation of different-sized particles in vertical chute flow. We find that, for low solid fractions, large particles segregate toward regions of low shear rates where the granular temperature (velocity variance) is low. As the solid fraction increases, this trend reverses, and large particles segregate toward regions of high shear rates and temperatures. We find that this is a global phenomenon: local segregation trends reverse at high system solid fractions even where local solid fractions are small. The reversal corresponds to the growth of a single enduring cluster of 30%-60% of the particles that we propose changes the segregation dynamics.
我们通过计算研究了在垂直滑槽流中不同大小颗粒的剪切诱导分离。我们发现，对于低固相分数，大颗粒会向剪切率低的区域（即颗粒温度（速度方差）低的区域）分离。随着固相分数的增加，这种趋势发生逆转，大颗粒向剪切率和温度较高的区域分离。我们发现，这是一个普遍现象：即使在局部固相分数较小的情况下，在高系统固相分数下，局部分离趋势也会发生逆转。这种逆转对应于一个持久的 30%-60%颗粒团簇的形成，我们提出这个团簇改变了分离动力学。
