Bridging the Spatial and Temporal Scales in Dense Granular Systems Description of Dense Granular Shear Flows

弥合稠密粒状系统中的时空尺度 稠密粒状剪切流的描述

• 批准号: 0605857
• 负责人: Lou Kondic
• 金额: --
• 依托单位: New Jersey Institute of Technology
• 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: 2006-08-15 至 2009-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0605857&HistoricalAwards=false
• 关键词: Bridging; Spatial; Temporal; Scales; Dense

KondicDMS-0605857 The project centers on analyzing and understanding thenature of information propagation through dense granular systems. The properties of the signals are then used to deduce the basicphysical mechanisms of the force and energy transmission. Thesemechanisms have been the subject of considerable study latelybecause it is crucial to understand whether the forces betweengranular particles propagate in a manner that can be describedunder an elliptic, hyperbolic, or parabolic framework. Thestarting point of this project is development of large scalediscrete element simulations that are used to analyze response ofdense granular systems to space- and time-dependentperturbations. The results of the simulations are then employedto help formulate effective models for bridging the scalesbetween micro (grain scale) and meso (hundreds or thousands ofgrains) descriptions of granular systems. Both static anddynamic granular systems are considered, making it possible toanalyze the interplay between granular dynamics and signalpropagation. This setup also allows for considering someimportant features of dense granular flows, such as the role offorce anisotropy and underlying microstructure. The project iscarried out in close collaboration with experimental workperformed at Duke University. Dense granular systems are one of the most challengingsystems in the field of soft condensed matter, in particularbecause they are subject to jamming, and fall in between solidand liquid states of matter. Analysis of signal propagationthrough these systems allows us to understand how granularity ona micro scale influences macroscale behavior. The novel researchtechniques used here also can be applied to other soft condensedmatter systems that experience jamming, such as emulsions,colloids, gels, and foams. In addition, signal propagationthrough granular systems is of considerable importance in anumber of practical problems including oil recovery,vibrofluidized beds, and some important humanitarian efforts,such as detection of land mines. The project addresses basicissues in statics and dynamics of dense granular systems;understanding of these basic concepts allows for future progressin developing better models needed for numerous applications ofgranular materials.

KondicDMS-0605857 该项目的重点是分析和理解通过密集颗粒系统的信息传播的性质。然后利用这些信号的性质来推断力和能量传递的基本物理机制。 这些机制一直是相当多的研究课题，因为它是至关重要的，以了解是否颗粒之间的力量传播的方式，可以描述下椭圆，双曲线，或抛物线框架。 该项目的出发点是大规模离散元模拟的发展，用于分析稠密颗粒系统对空间和时间相关扰动的响应。 模拟的结果，然后employedto帮助制定有效的模型之间的桥梁scalesbetween微观（晶粒尺度）和介观（数百或数千粒）的颗粒系统的描述。 静态和动态的颗粒系统被认为是，使之成为可能toseanalyze颗粒动力学和信号传播之间的相互作用。 这种设置也允许考虑致密颗粒流的一些重要特征，如力各向异性和底层微观结构的作用。该项目是与杜克大学的实验工作密切合作进行的。 致密颗粒系统是软凝聚态领域中最具挑战性的系统之一，特别是因为它们容易堵塞，并且处于固体和液体状态之间。 通过分析这些系统的信号传播，我们可以了解微观尺度的粒度如何影响宏观尺度的行为。 这里使用的新的研究技术也可以应用到其他软凝聚物质系统，经验堵塞，如乳液，胶体，凝胶和泡沫。 此外，通过颗粒系统的信号传播是相当重要的实际问题，包括石油回收，振动流化床，和一些重要的人道主义工作，如探测地雷。 该项目解决了致密颗粒系统的静态和动态的基本问题;理解这些基本概念可以为颗粒材料的许多应用开发更好的模型。