Non-local continuum modelling of steady, dense granular heap flows
Non-local continuum modelling of steady, dense granular heap flows
复制标题
稳定、密集颗粒堆流的非局部连续模型
DOI：
10.1017/jfm.2017.554
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发表时间：
2017
影响因子：
3.7
通讯作者：
Henann, David L.
中科院分区：
文献类型：
--
作者：
Liu, Daren;Henann, David L.
密集的颗粒堆流在自然界中很常见，例如在雪崩和山体滑坡期间，以及在工业流动中。在颗粒堆流中，快速流动集中在自由表面附近，快速流动层的厚度与总体流速有关。在地表以下深层区域，指数衰减蠕变流占主导地位，特征衰减长度仅取决于几何形状，而不取决于总流量。现有的基于局部本构方程的致密颗粒流连续体模型不能同时预测这两种实验观察到的特征——甚至不能预测地表下蠕动流动的存在。在这项工作中，我们应用尺度依赖连续体方法-非局部颗粒流动性模型-在两个光滑的摩擦侧壁之间的堆上稳定，密集的颗粒流动。我们表明，该模型捕捉了流速依赖的、快速流动的面层和流速独立的、在稳定流动条件下缓慢爬行的体的显著特征。
Dense granular heap flows are common in nature, such as during avalanches and landslides, as well as in industrial flows. In granular heap flows, rapid flow is localized near the free surface with the thickness of the rapidly flowing layer dependent on the overall flow rate. In the region deep beneath the surface, exponentially decaying creeping flow dominates with characteristic decay length depending only on the geometry and not the overall flow rate. Existing continuum models for dense granular flow based upon local constitutive equations are not able to simultaneously predict both of these experimentally observed features – failing to even predict the existence of creeping flow beneath the surface. In this work, we apply a scale-dependent continuum approach – the non-local granular fluidity model – to steady, dense granular flows on a heap between two smooth, frictional side walls. We show that the model captures the salient features of both the flow-rate-dependent, rapidly flowing surface layer and the flow-rate-independent, slowly creeping bulk under steady flow conditions.