Collaborative Research: Self-Assembly and Aggregate Formation in Stratified Fluids

合作研究：分层流体中的自组装和聚集体形成

基本信息

批准号：
1910824
负责人：
Richard McLaughlin
金额：
$ 25.4万
依托单位：
University of North Carolina at Chapel Hill
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
2019
资助国家：
美国
起止时间：
2019-07-01 至 2023-06-30
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=1910824&HistoricalAwards=false
关键词：
Collaborative Research Self Assembly Aggregate

项目摘要

The atmospheres, lakes, and oceans of our world typically involve density variability, with layers of lighter fluid sitting on top of heavier fluid. In this project, we are exploring a novel mechanism we have discovered through which particles suspended within such layered systems are seen to attract each other and self-assemble, forming large disc like clusters. The mechanism for this attraction involves fluid flows which the particles themselves create from being in a layered fluid. Such clusters occur ubiquitously in lakes and oceans, where they can provide food sources for a variety of organisms, or result in concentrations of polluting particles. The origins of these clusters may well lie within this new aggregate formation mechanism under exploration within this award. Graduate students will be involved in the project. Specifically, the award will undertake a combined theoretical, numerical, and experimental investigation of a newly discovered hydrodynamic interaction between particles in a stratified ambient environment. Recent experimental work by the PIs at the UNC Joint Fluids Lab have demonstrated that passive particles suspended in a density-stratified environment interact through self-induced flows which can result in approaching one and another over time until coming into contact. Collections of many particles tend to aggregate and self-assemble into large-scale 2D structures due to this newly identified attraction mechanism. The project aims to characterize this newly-identified interaction effect in nature for the first time, through novel asymptotic methods, numerical simulations, and careful experimentation. The research will explore the complex interplay between diffusion, advection, and geometry (through physical boundary conditions) in inducing new collective phenomena. This requires developing novel computational, asymptotic, and experimental methods for extracting quantitative predictions from the parent Navier-Stokes equations coupled through the viscous stress tensor to particles suspended in stratified environments. The new asymptotic methods developed as part of this proposal will also prove useful for a wider range of problems in fluid dynamics and potential theory.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

我们世界的大气，湖泊和海洋通常涉及密度变化，较轻的液体含有较轻的液体。在这个项目中，我们正在探索一种新的机制，我们发现了通过该机制悬浮在此类分层系统中的粒子可以彼此吸引并自组装，从而形成大型圆盘之类的簇。这种吸引力的机制涉及颗粒本身通过分层流体产生的流体流动。这种簇无处不在地发生在湖泊和海洋中，它们可以为各种生物提供食物来源，或者导致污染颗粒的浓度。这些集群的起源很可能位于该奖项中的这种新的总体形成机制中。研究生将参与该项目。具体而言，该奖项将对分层环境中颗粒之间新发现的水动力相互作用进行合并的理论，数值和实验研究。 PI在UNC关节液实验室的最新实验工作表明，悬浮在密度分层环境中的被动颗粒通过自我诱导的流动相互作用，这可能会随着时间的流逝而接近一个和另一个，直到接触。由于这种新鉴定的吸引机制，许多颗粒的集合倾向于将许多颗粒集合成大规模的2D结构。该项目旨在通过新颖的渐近方法，数值模拟和仔细的实验来首次表征本质上这种新识别的相互作用效应。这项研究将探索诱导新的集体现象的扩散，对流和几何形状（通过物理边界条件）之间的复杂相互作用。这需要开发新的计算，渐近和实验方法，以通过粘性应力张量耦合到悬浮在分层环境中的颗粒中提取定量预测。作为该提案的一部分开发的新的渐近方法也将被证明对流体动力和潜在理论的更广泛问题有用。该奖项反映了NSF的法定任务，并被认为是值得通过基金会的知识分子和更广泛影响的评估来支持的。审查标准。