The use of the geotechnical centrifuge to obtain scaled physical models is a useful tool in geomechanics. When dealing with granular flows, however, the traditional scaling principles are challenged by the complex rheology of the material and by the non-trivial effects of the Coriolis apparent acceleration. In a laboratory centrifuge, obtaining a clear understanding of these effects is further complicated by the technical difficulties in obtaining flows in steady conditions. In this work, the scaling principles for granular flows are studied using a numerical model based on the discrete-element method. In this way it is possible to obtain a steady flow in a rotating reference frame, and to explore the variation of macroscopic properties by changing the scaling factor and the distance from the rotation centre. The outcome is compared with the prediction obtained with a continuum theory for frictional flows. Results show that granular flows scale consistently only when the Coriolis acceleration is negligible, and are severely altered otherwise. The augmented acceleration field is also responsible for an alteration of the flow state, driving the system towards the inertia-driven collisional regime.

中文翻译：

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离心加速度场中的颗粒流模拟

使用岩土离心机获得缩放的物理模型是岩土力学中的有用工具。但是，当处理颗粒状流动时，传统的缩放原理会受到材料复杂的流变性和科里奥利表观加速度的不平凡影响的挑战。在实验室离心机中，在稳定条件下获得流量的技术难题使对这些影响的清晰了解更加复杂。在这项工作中，使用基于离散元素方法的数值模型研究颗粒流的缩放原理。通过这种方式，可以在旋转参考系中获得稳定的流量，并可以通过更改比例因子和距旋转中心的距离来探索宏观特性的变化。将结果与通过连续流理论获得的摩擦流预测进行比较。结果表明，只有当科里奥利加速度可忽略不计时，粒状流才会始终如一地缩放，否则将发生严重变化。增强的加速度场还负责流动状态的改变，从而将系统推向惯性驱动的碰撞状态。