RUI: Elongated Granular Materials: Simulation and Experiment

摘要：沙堆是一个堵塞系统的例子：沙粒不能相互移动，沙堆相对稳定。成堆的棒材比那些圆形颗粒要坚硬得多。这就提出了一些有趣的物理问题，比如这两个系统在微观层面上的区别是什么，粒子的几何形状在它们的阻塞和流动中扮演了什么角色？这些问题的答案在石油开采中也有重要的工业应用。这些系统相对来说还没有被探索过。该项目寻求对颗粒形状如何影响阻塞状态的开始和稳定性的新理解。该项目侧重于棒状颗粒材料系统的计算和实验框架的发展。模拟结果将与实验结果进行比较，以揭示普通颗粒材料的现有理论如何随着颗粒被拉长而分解。该项目将培养本科生的科学实验和计算方法。在该项目的教育部分，一个只招收本科生的院校联盟将评估本科生物理研究的影响。调查和焦点小组的结果将使院校能够有效地扩大和提供如何加强本科生研究经验的见解。技术摘要：成堆的细长颗粒颗粒明显比那些圆形颗粒更坚硬，提出了许多有趣的物理问题，以及对工业应用的重要影响。本项目侧重于新的计算和实验研究方法，以探索颗粒形状对堵塞状态的影响作为颗粒长径比的函数。模拟将结合静摩擦的现实模型（这是干扰过渡的关键组成部分），并将结果与使用旋转鼓和料斗进行的实验进行比较，这些实验测量了临界休止角和干扰概率（作为颗粒长径比、材料特性和系统尺寸/尺寸的函数）。该项目将培养本科生的科学实验和计算方法。在该项目的教育部分，一个只招收本科生的院校联盟将评估本科生物理研究的影响。调查和焦点小组的结果将使院校能够有效地扩大和提供如何加强本科生研究经验的见解。

NONTECHNICAL ABSTRACT: A sandpile is an example of a jammed system: the grains cannot move around one another and the pile is relatively stable. Piles of rods are significantly more rigid than those of round particles. This raises intriguing physics questions, such are what is the difference in the two systems at the microscopic level and what role does the geometrical shape of particles play in their jamming and flow? Answers to these questions also have important industrial applications in oil recovery. These systems haev remained relatively unexplored. This project seeks a new understanding of how particle shape influences the onset and stability of the jammed state. This project focuses on the development of a computational and experimental framework for systems of rod-like granular materials. Results of simulations will be compared with experiments to reveal how existing theories of ordinary granular materials break down as particles become elongated. The project will train undergraduate students in scientific experimental and computational methods. Under the education component of the project, a coalition of undergraduate-only institutions will assess the impact of undergraduate physics research. Results from surveys and focus groups will enable institutions to effectively broaden and provide insights in to how to strengthen the undergraduate research experience.TECHNICAL ABSTRACT: Piles of elongated granular particles are significantly more rigid than those of round particles, presenting a number of intriguing physics questions, as well as having important consequences for industrial applications. This project focuses on new computational and experimental research methods to probe the effects of the particle shape on the jammed state as a function of particle aspect ratio. Simulations will incorporate realistic models for static friction --- a critical component of the jamming transition --- and the results will be compared with experiments performed using rotating drums and hoppers that measure critical angles of repose and jamming probability as functions of particle aspect ratio, material properties, and system size/dimension. The project will train undergraduate students in scientific experimental and computational methods. Under the education component of the project, a coalition of undergraduate-only institutions will assess the impact of undergraduate physics research. Results from surveys and focus groups will enable institutions to effectively broaden and provide insights in to how to strengthen the undergraduate research experience.