Abstract

Granular flows are typically studied in laboratory flumes based on common similarity scaling, which create stress fields that only roughly approximate field conditions. The geotechnical centrifuge produces stress conditions that are closer to those observed in the field, but steady conditions can be hardly achieved. Moreover, secondary effects induced by the apparent Coriolis acceleration, which can either dilate or compress the flow, often obscure scaling. This work aims at studying a set of numerical experiments where the effects of the Coriolis acceleration are measured and analyzed. Three flow states are observed: dense, dilute, and unstable. It is found that flows generated under the influence of dilative Coriolis accelerations are likely to become unstable. Nevertheless, a steady dense flow can still be obtained if a large centrifuge is used. A parametric group is proposed to predict the insurgence of instabilities; this parameter can guide experimental designs and could help to avoid damage to the experimental apparatus and model instrumentation.

Graphic abstract

中文翻译：

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科里奥利诱导的颗粒流离心模型的不稳定性

摘要

通常在实验室水槽中基于共同的相似度标度研究颗粒流，这会产生仅大致近似田间条件的应力场。岩土离心机产生的应力条件与现场观察到的条件更接近，但很难达到稳定的条件。此外，由表观科里奥利加速度引起的二次效应通常会掩盖水垢，后者可能使流量膨胀或压缩。这项工作旨在研究一组数值实验，在其中测量和分析科里奥利加速度的影响。观察到三种流动状态：稠密，稀薄和不稳定。已经发现，在科里奥利膨胀加速度的影响下产生的流动可能变得不稳定。但是，如果使用大型离心机，仍可获得稳定的致密流。提出了一个参数组来预测不稳定性的发生。该参数可以指导实验设计，并有助于避免损坏实验设备和模型仪器。

图形摘要