CAREER: Instabilities in the Flow of Dry and Wet Granular Matter

9983659这个CAREER项目将通过实验研究在各种激发和边界条件下，粘性和非粘性颗粒物质流动的不稳定性，这些激发和边界条件会导致颗粒流动、模式或分离。对于颗粒状物质，没有类似于流体的纳维尔-斯托克斯方程的基本理论方法。发展综合理论的一个重要障碍是缺乏对颗粒物质的定量实验。使用筒仓系统和库埃特剪切流池的拟议研究结果将对新开发的水动力方法的适用范围进行关键测试，特别是考虑到最近的数值工作，该工作显示即使名义耗散也明显破坏了水动力，并提出了关于其他连续介质方法适用性的问题。一门新的以实验为基础的课程将以自然界的非线性现象为基础，作为本科物理课程和暑期高中教师培训计划的一部分。这个凝聚态物理CAREER项目是对干湿颗粒物质性质的实验研究。颗粒物质，如沙子或颗粒，在许多工程过程和地质现象中都很重要，但对其性质的满意描述并不存在。利用高速和高分辨率成像技术的实验将检验不同几何形状的颗粒材料，以确定它们在外加能量机制下的性质。从拟议的实验中获得的基本理解将最终导致对一系列现象的更好理解，例如导致山体滑坡长期径流的条件，以及漏斗流中颗粒的分离。一门名为“自然模式”的新实验课程将作为本科物理课程和暑期高中教师培训计划的一部分。实验的撰写和设计将在网络上提供，以弥补目前非线性物理教科书中强调做实验的不足

9983659This CAREER project will investigate experimentally the instabilities in the flow of cohesive and non-cohesive granular matter under a variety of excitations and boundary conditions that lead to granular flows, patterns, or segregation. There is no fundamental theoretical approach for granular matter similar to the Navier--Stokes equations for fluids. An important deterrent to the development of a comprehensive theory has been lack of quantitative experiments on granular matter. The results of the proposed studies using silo systems, and couette shear flow cells will yield critical tests of the range of applicability of newly developed hydrodynamic approaches, especially in light of recent numerical work which shows a clear breakdown of hydrodynamics for even nominal dissipation and raises questions about the applicability of other continuum approaches. A new laboratory-based course will be developed on nonlinear phenomena in nature as part of the undergraduate physics curriculum and a summer high school teacher training program.%%%This condensed matter physics CAREER project is an experimental study of the properties of dry and wet granular matter. Granular matter, like sand or grain, is important in many engineering processes and geological phenomena, but a satisfactory description of its properties does not exist. The proposed experiments using high speed and high resolution imaging will examine granular materials in various geometries to determine their properties under external mechanisms of adding energy. The basic understanding gained from the proposed experiments will ultimately lead to a better understanding of a range of phenomena such as conditions that give rise to long run-offs in landslides, and segregation of grains in hopper flows. A new laboratory-based course called "Patterns in Nature" will be developed as part of the undergraduate physics curriculum and a summer high school teacher training program. The write-ups and the designs for the experiments will be made available on the Web to offset the current lack in textbooks in nonlinear physics with emphasis on doing experiments.***