Fluctuations and Flow for Granular Materials

小行星9802602 这个凝聚态物理项目将主要通过实验来探索颗粒材料的动力学，但也有一些理论和计算。 代表了三个领域。 第一个是缓慢颗粒流中波动的作用。实验将提供精确的局部和全球措施的波动力和静态和缓慢剪切粒子合奏，包括二维和三维配置的运动学特性。目标是提供这些波动的长度和时间尺度的定量测量，并指导包括波动影响的模型的开发。第二是在惯性制度的特点是二元碰撞颗粒流的表征。 实验将描述碰撞粒子的集体动力学，以及具有 持续不断的能量输入最后，实验配置将探测 气体 在细颗粒材料中流动， 眼睛 为了定量地了解震动的堆积效应， 粒状材料 粒状 所有类型的流动都是 高度 重要商业，这个项目是应该贡献的知识，是技术上相关的，为学生和博士后在基础和应用领域提供良好的培训。 %这个 简明 物质物理项目是 集中 对 更好地理解颗粒材料的流动。 这些材料无处不在，包括粮食、矿石、煤炭和药品，仅举几例。这些材料的加工对许多行业至关重要，然而，对于如何描述这些材料还没有一个坚实的科学认识。因此，涉及粒度处理的过程通常以设计效率的2/3运行，并且灾难性故障频繁发生。该项目确定了三个研究领域，这些领域将提供更深入的科学理解，并具有应用于商业过程的潜力。对于缓慢流动的系统，我们将描述波动的性质，已知波动很大，因此具有潜在的破坏性，但特征很差。对于快速搅拌/摇动的系统，实验将根据这些系统与气体的相似性来测试模型。 最后，对于足够小的颗粒，例如典型的沙子， 催化剂或粉末，环境空气流 是 重要. 实验 将描述 粮食 周围的气体。 该项目还将为一到两名研究生提供技术职业培训，并为博士后研究人员和本科生提供培训。 ***

9802602 Behringer This condensed matter physics project will probe the dynamics of granular materials primarily via experiments but with some theory and computation. Three areas are represented. First is the role of fluctuations in slow granular flows. Experiments will provide precise local and global measures of fluctuations in forces and in kinematic properties of static and slowly sheared ensembles of particles, including both two- and three-dimensional configurations. The goal is to provide a quantitative measure of the length and time scales for these fluctuations, and to guide the development of models that include the effects of fluctuations. Second is the characterization of granular flows in the inertial regime characterized by binary collisions. Experiments will characterize the collective dynamics of colliding particles, and the thermal-like properties of ensembles with a continuous input of energy. Finally, experimental configurations will probe gas flow in fine granular materials, with an eye to quantitatively understanding heaping effects for shaken granular materials. Granular flows of all types are highly important commercially, and this project is should contribute knowledge that is technically relevant, as provide excellent training for students and post-docs in both fundamental and applied areas. %%% This condensed matter physics project is focused on better understanding the flow of granular materials. Such materials are ubiquitous and include food grains, ore, coal, and pharmaceuticals, to name only a few. The processing of these materials is vital to many industries, yet, there is not a solid scientific understanding of how to describe these materials. As a consequence, processes involving granular processing typically operate at 2/3 of design efficiency, and catastrophic failures are frequent. This proje ct identifies three areas of study that will provide deeper scientific understanding with the potential for applications to commercial processes. For slowly flowing systems, we will characterize the nature of fluctuations, which are known to be large, and therefore potentially destructive, but are poorly characterized. For rapidly stirred/shaken systems, experiments will test models based on the similarity of these systems to a gas. Finally, for grains that are small enough, such as typical sand, cracking catalyst, or powder, ambient air flow is important. Experiments will characterize the interplay between grain and surrounding gas. This project will also provide technical career training for one to two graduate students as well as training for post- doctoral researchers and undergraduates. ***