Granular Shear Instabilities: Oscillations, Waves and Rolls?

粒状剪切不稳定性：振荡、波浪和滚动？

• 批准号: 0070591
• 负责人: Troy Shinbrot
• 金额: $ 6.8万
• 依托单位: Rutgers University New Brunswick
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-02-01 至 2001-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0070591&HistoricalAwards=false
• 关键词: Granular; Shear; Instabilities; Oscillations; Waves

AbstractCTS-0070591T. Shinbrot and B.J. Glasser, Rutgers University - New BrunswickIt is proposed to investigate the flow microstructure and instabilities in rapid flow of two particle streams past a splitter plate. This is a simple flow geometry where fundamental aspects can be studied, such as the type of instability, typical velocity and vorticity flow structures, the shape of the interface among streams, dimensionless numbers governing the transition, and the role of interparticle stick-slip phenomenon on instabilities. The research was triggered by observations made on a small-scale experiment where unexpected indications of Kelvin-Helmholtz type instabilities have been noticed. The main experiment is based on flow visualization of a quasi-two-dimensional flow using colored and tracer particles at the confluence of two particulate streams. The effect of particle size on various shear flow patterns, including collective behavior of particle motion in large vortices and rollers, will be experimentally determined. This exploratory research aims to establish the flow pattern in a relatively simple shear flow and to derive conclusions for the basic flow mechanisms in particle systems of various particle sizes from micron to nanosize.If successful, this proof of concept projects may have applications in mixing, in chemical and pharmaceutical processing industry, in polymer and ceramics processing.

摘要CTS-0070591 T。本文研究了两股颗粒流快速流过分流板时的流动微观结构和不稳定性。 这是一个简单的流动几何形状，可以研究的基本方面，如类型的不稳定性，典型的速度和涡量流结构，流之间的界面的形状，无量纲数控制的过渡，和颗粒间粘滑现象的作用不稳定性。 这项研究是由一个小规模实验的观察引发的，在这个实验中，人们注意到了开尔文-亥姆霍兹型不稳定性的意想不到的迹象。 主要的实验是基于准二维流的流动可视化，在两个颗粒流的汇合处使用彩色和示踪粒子。 将通过实验确定颗粒尺寸对各种剪切流模式的影响，包括大涡流和滚柱中颗粒运动的集体行为。 该探索性研究旨在建立相对简单的剪切流中的流动模式，并得出从微米到纳米尺寸的各种颗粒系统中的基本流动机制的结论。如果成功，该概念验证项目可能在混合，化学和制药加工工业，聚合物和陶瓷加工中应用。