Suspensions and Granular Media: Wet vs. Dry

悬浮液和颗粒介质：湿法与干法

• 批准号: 0828563
• 负责人: John Brady
• 金额: $ 30万
• 依托单位: California Institute of Technology
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-09-01 至 2012-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0828563&HistoricalAwards=false
• 关键词: Suspensions; Granular; Media; Wet; vs.

CBET-0828563BradyProject SummaryIntellectual Merit: Suspensions and granular media are found widely in nature and industry. And although the two fields have developed independently, recently it has been noted that viscous suspensions and dry granular materials often display similar flow phenomena. Despite the similarities, the two fields nevertheless remain separate. Here we propose that this separation is unnecessary and that suspensions and granular media - wet and dry - actually correspond to different limiting behaviors of one common system. The linking parameter is the Stokes number - the ratio of the inertial to shear forces: small Stokes numbers correspond to viscous suspensions and high Stokes numbers to dry granular media. The proposed research is a simulation study covering the entire range of Stokes numbers (and concentrations) and thus explores the flow behavior and rheological connection between these two fields. Not only will we learn about this connection, we may also advance our understanding of both suspensions and granular media. This study also provides vital rheological data (shear and normal stresses, shear-induced diffusivities, microstructures, etc.) for inertial suspensions, of which there appears to be surprisingly little.Broader Impact: In a broader context, this research will help elucidate the behavior of an often called new state of matter - granular matter. Granular flow forms part of the larger area of multiphase flow with applications ranging from sediment transport in rivers and bays, to pneumatic conveying of minerals, to the production of pharmaceutical powders. The work will also engage PhD students who will become experts in computational methods, multiphase fluid physics and rheology. This research provides the foundation for modeling multiphase flows that has widespread application in science and technology.

CBET-0828563Brady项目摘要智力优点：悬浮液和颗粒介质在自然界和工业中广泛存在。尽管这两个领域是独立发展的，但最近人们注意到粘性悬浮液和干燥颗粒材料经常表现出类似的流动现象。尽管有相似之处，但这两个领域仍然是分开的。在这里，我们建议这种分离是不必要的，悬浮液和颗粒介质（湿的和干的）实际上对应于一个常见系统的不同限制行为。连接参数是斯托克斯数 - 惯性力与剪切力的比率：小斯托克斯数对应于粘性悬浮液，高斯托克斯数对应于干燥颗粒介质。拟议的研究是一项涵盖斯托克斯数（和浓度）整个范围的模拟研究，从而探讨了这两个领域之间的流动行为和流变联系。我们不仅可以了解这种联系，还可以加深对悬浮液和颗粒介质的理解。这项研究还提供了惯性悬架的重要流变数据（剪切和法向应力、剪切引起的扩散系数、微观结构等），而这些数据似乎少得可怜。 更广泛的影响：在更广泛的背景下，这项研究将有助于阐明通常称为新物质状态——粒状物质的行为。颗粒流是更大范围的多相流的一部分，其应用范围从河流和海湾中的沉积物运输到矿物的气力输送，再到药粉的生产。这项工作还将吸引博士生，他们将成为计算方法、多相流体物理学和流变学方面的专家。这项研究为在科学技术中广泛应用的多相流建模提供了基础。