A Scale analysis of axisymmetric granular column collapses over a range of elevated gravitational accelerations

颗粒流既可以在自然界中找到，如滑坡，泥石流和落石，也可以在一系列行业中找到，如食品和制药加工。在这项研究中，我们专注于环境设置，其中颗粒流通常因水的存在和存在的巨大颗粒尺寸范围而变得复杂。这两个因素在创建实验室原型时极大地改变了这些流的缩放。一个最简单的和充分研究的实验室规模表示这些现象是一个轴对称颗粒柱的崩溃。我们将以此为出发点，探索湿度、饱和度和颗粒大小的影响，其数量级为10^6。为了在实验室尺度上物理地表示真实的泥石流中的流体的影响，我们必须人为地增加由于重力引起的加速度，使得g依赖的速率保持平衡，尽管物理上流动小得多。计划开发一个轴对称颗粒柱倒塌实验，该实验将能够安装在位于大学公园L2楼的土工离心机上，以便在一系列升高的重力加速度下进行测试。饱和度;粒度和级配;样品纵横比。 分析这些实验的孔隙压力和图像数据，并与已发表的干柱塌陷数据和真实的泥石流数据进行比较。确定哪些动态过程决定流量结果由哪些颗粒尺寸范围控制。 在简单的分析模型和可扩展的数值模型中实现这些发现。

Granular flows can be found both in nature, as landslides, debris flows and rockfalls, and across a range of industries, such as food and pharmaceutical processing. In this research, we focus on the environmental setting, where the granular flow is typically complicated by the presence of water and a huge range of particle sizes present. These two factors greatly alter the scaling of these flows when creating laboratory prototypes. One of the most simplistic and well researched laboratory scale representations of these phenomena is the collapse of an axisymmetric granular column. We will use this starting point to explore the effects of moisture, saturation and particle sizes ranging by orders of magnitude of 10^6. In order to physically represent the effects of fluid within a real debris flow at laboratory scale, we must artificially increase acceleration due to gravity, so that the g-dependent rates stay in balance despite physically much smaller flows. It is planned to develop an axisymmetric granular column collapse experiment that will be able to be mounted to the geotechnical centrifuge located in the L2 building on University Park in order to conduct tests over a range of elevated gravitational accelerations.The chief outcomes of the project are as follows: To develop a comprehensive database of axisymmetric granular column collapse experiments, varying parameters; gravitational acceleration; saturation level; particle size and grading; sample aspect ratio. To analyse pore pressure and image data from these experiments and compare with published dry column collapse data, and data from real debris flows. Establish which dynamic processes determining flow outcomes are governed by which particle size ranges. To implement these findings within simple analytical models and scalable numerical models.