Granular materials composed of particles with differing grain sizes, densities, shapes, or surface properties may experience unexpected segregation during flow. This review focuses on kinetic sieving and squeeze expulsion, whose combined effect produces the dominant gravity-driven segregation mechanism in dense sheared flows. Shallow granular avalanches that form at the surface of more complex industrial flows such as heaps, silos, and rotating drums provide ideal conditions for particles to separate, with large particles rising to the surface and small particles percolating down to the base. When this is combined with erosion and deposition, amazing patterns can form in the underlying substrate. Gravity-driven segregation and velocity shear induce differential lateral transport, which may be thought of as a secondary segregation mechanism. This allows larger particles to accumulate at flow fronts, and if they are more frictional than the fine grains, they can feedback on the bulk flow, causing flow finge...

中文翻译：

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密集颗粒流中的颗粒分离

由具有不同粒度、密度、形状或表面特性的颗粒组成的颗粒材料在流动过程中可能会出现意外的分离。本综述侧重于动力筛分和挤压排出，它们的组合效应在密集剪切流中产生主要的重力驱动分离机制。在堆、筒仓和转鼓等更复杂工业流的表面形成的浅颗粒雪崩为颗粒分离提供了理想的条件，大颗粒上升到表面，小颗粒渗透到底部。当这与侵蚀和沉积相结合时，可以在下面的基底中形成惊人的图案。重力驱动的离析和速度剪切会导致不同的横向输运，这可以被认为是一种二次离析机制。