Collaborative Research: Drag Rules for Quasi-Static Granlar Media - Experimental and Numerical Studies

协作研究：准静态 Granlar 介质的阻力规则 - 实验和数值研究

• 批准号: 0625139
• 负责人: JC Santamarina
• 金额: $ 4.6万
• 依托单位: Georgia Tech Research Corporation
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-09-01 至 2008-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0625139&HistoricalAwards=false
• 关键词: Collaborative; Research; Drag; Rules; Quasi

ABSTRACTProposal Numbers: 0626191 and 0625139Principal Investigators: Koehler, Stephan and Santamaria, J. CarlosAffiliations: Emory University and Georgia Tech Research CorporationProposal Title: Collaborative Research: Drag Rules for Quasi-Static Granular Media Experimental and Numerical StudiesIntellectual Merit:The flow of dense granular matter is technologically important, but poorly understood. Competing models of dense granular matter are based upon different physical assumptions, that have enough free parameters to allow for general agreement with experimental observations. The number of experimental model systems is relatively small, and they are typically characterized by a high degree of symmetry involving simple flows, such as plane shear or Couette flow. In order to advance understanding of dense granular flow, a larger and richer variety of model systems needs to be considered.Two research teams, one from the Emory physics department and another from the Georgia Tech civil engineering department will collaboratively investigate the dynamics of intruders in dense granular media. Four inter-related projects are proposed: 1) Force and flowfield measurements of intruders moving vertically through static granular media, 2) Dependence of drag forces on the intruder's orientation, 3) Variations of intruder drag forces due to shearing of granular matter, and 4) Interactions between two intruders mediated through the granular medium. The Emory team will perform the physical experiments; the Georgia Tech team will simulate these four systems using a commercially available discrete element code and the equivalent frictional continuum Cam Clay model. The experimental results will verify that the code is accurate, and the numerical simulations will provide insight into experimentally inaccessible quantities, such as the flow fields and fabric. The proposed studies will provide phenomenological rules for the resistive forces on intruders, and the results will enable theorists to determine the validity of physical assumptions upon which their models are based. These rules will be of practical use for developing new methods of handling granular matter and for understanding how certain desert animals swim through sandy environments.Broader Impact:Procedures will be developed for determining the in situ, local rheology within granular beds based upon intruder drag. These procedures will enhance processing of granular matter in many different settings, varying from conveyer belts to mixing of pharmaceutical powders. This program will build an exciting, synergistic and interdisciplinary environment, by combining teams from two different universities and disciplines, with each team studying the same systems but using different approaches. These interactions will also prompt inter-disciplinary teaching of a soft condensed matter physics course and a fundamentals of granular matter course. Additional activities include undergraduate and graduate research participation, creation of web-based teaching modules, and interactions with desert biologists.

建议编号：0626191和0625139主要调查人员：Koehler，Stephan和Santamaria，J.Carlos关系：埃默里大学和佐治亚理工学院研究公司建议标题：合作研究：准静态颗粒介质实验和数值研究的阻力规则智力价值：稠密颗粒物质的流动在技术上很重要，但了解得很少。致密颗粒物质的相互竞争的模型基于不同的物理假设，这些假设具有足够的自由参数，以允许与实验观测大体一致。实验模型系统的数量相对较少，它们的典型特征是涉及简单流动的高度对称性，如平面剪切或Couette流动。为了促进对稠密颗粒流的理解，需要考虑更大更丰富的模型系统。两个研究小组，一个来自埃默里物理系，另一个来自佐治亚理工学院土木工程系，将合作研究稠密颗粒介质中入侵者的动力学。提出了四个相互关联的方案：1)入侵者在静态颗粒介质中垂直运动的作用力和流场测量，2)阻力与入侵者方位的关系，3)颗粒物质剪切引起入侵者阻力的变化，以及4)两入侵者之间通过颗粒介质的相互作用。埃默里团队将进行物理实验；佐治亚理工学院团队将使用商业上可用的离散元代码和等效摩擦连续介质凸轮粘土模型来模拟这四个系统。实验结果将验证程序的准确性，数值模拟将提供对实验无法获得的量的洞察，如流场和布料。拟议的研究将为入侵者的阻力提供现象学规则，结果将使理论家能够确定他们的模型所基于的物理假设的有效性。这些规则将对开发处理颗粒物质的新方法和了解某些沙漠动物如何在沙质环境中游泳有实际用处。广泛影响：将开发基于入侵者阻力确定颗粒床内就地、局部流变性的程序。这些程序将在许多不同的环境中加强颗粒物质的处理，从传送带到药物粉末的混合。该计划将建立一个令人兴奋的、协同的和跨学科的环境，将来自两个不同大学和学科的团队结合起来，每个团队研究相同的系统，但使用不同的方法。这些相互作用也将促进软凝聚态物理课程和颗粒物质基础课程的跨学科教学。其他活动包括参与本科生和研究生研究，创建基于网络的教学模块，以及与沙漠生物学家互动。