Abstract A viscous fluid confined in a closed channel has two flow patterns, namely a laminar flow and a turbulent flow. Although already the onset and properties of each pattern have extensively been explored in various geometric fluid systems, very little is known about the flow pattern of a discrete medium. Thus, herein, we reported an experimental study on the type of flow in a vertically vibrated, annular, and granular system. It was found that the system presents either a laminar granular flow or a turbulent granular flow in different vibration modes. With the help of the Reynolds numbers of the granular system, the flow patterns were explained and identified. Finally, our results revealed a property peculiar to the granular flow which is similar to, albeit at the same time different from, viscous fluids.

中文翻译：

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振动颗粒系统中的层流和湍流

摘要 封闭通道内的粘性流体具有两种流动模式，即层流和湍流。尽管已经在各种几何流体系统中广泛探索了每种模式的开始和特性，但对离散介质的流动模式知之甚少。因此，在本文中，我们报告了关于垂直振动、环形和颗粒系统中流动类型的实验研究。发现系统在不同的振动模式下呈现层流颗粒流或湍流颗粒流。借助粒状系统的雷诺数，可以解释和识别流动模式。最后，我们的结果揭示了颗粒流特有的特性，它类似于粘性流体，但同时又不同于粘性流体。