Collaborative Research: Kinetic to Continuum Modeling of Active Anisotropic Fluids

合作研究：活性各向异性流体的动力学到连续体建模

• 批准号: 1517347
• 负责人: Qi Wang
• 金额: $ 17.43万
• 依托单位: University of South Carolina at Columbia
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-09-15 至 2019-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1517347&HistoricalAwards=false
• 关键词: Collaborative; Research; Kinetic; Continuum; Modeling

The principal investigators use mathematics and computation to model fluid-particle mixtures in which the individual particles are anisotropic (e.g., rod-like) and have their own propulsion mechanism. Examples arise in nature with suspensions of rod-like, flagella-propelled bacteria, in living cells where actin filaments provide structural integrity and molecular motors propel the filaments to achieve cellular function, and in high performance materials where catalytic nano-rods are suspended in a reactive solvent and propelled by chemical reactions. These systems share the remarkable feature of self-organization on scales in space and time far greater than those of the individual particles, translating to functionality across many scales. These diverse active particle-fluid systems have been previously modeled. Here the investigators undertake a unified theoretical and computational platform for such problems, which offers multiple benefits. A common mathematical structure reveals how these systems achieve their functional properties, informs which physical and chemical features allow the most efficient steering and optimization of the system toward desired properties, allows for a common computational platform, and allows one to incorporate additional degrees of freedom or perturb existing particle and fluid properties and predict their consequences. These advances have applications to enhance beneficial bacterial colonies and to disrupt harmful ones, to repair damaged cellular functions, and to design nano-composite materials with optimal properties. Graduate students are involved in the work of the project.The principal investigators develop a modeling and computational platform for active, anisotropic fluids, unifying three apparently diverse fluid systems (catalytic nano-rod dispersions, swimming bacterial suspensions, and motor-driven actin filament gels) for which models, analysis, algorithms, and simulations have so far evolved independently. The mathematical platform unifies previous results, spans kinetic to continuum spatial and temporal scales, and identifies a common leading-order mathematical structure at each scale of description as well as the lower-order structure that distinguishes among different active, anisotropic fluids. This structure guides analysis and algorithm development toward an understanding of, and predictive control over, the remarkable observed behavior of these fluid systems. The project aims to distinguish sensitivity to particle dimensions, aspect ratio, concentration, and activation energy, with direct application to active nano-rod dispersions, actin filament gels, and bacterial suspensions in confined and free surface flows.

主要研究人员使用数学和计算来建模流体粒子混合物，其中各个颗粒是各向异性的（例如，类似杆状），并具有自己的推进机制。 在活蛋白丝中提供结构完整性和分子电机的活细胞中，在本质上出现了示例在本质上发生的，具有类似杆状鞭毛的细菌，在活细胞中促进了细丝以实现细胞功能，而在高性能材料中，催化纳米棒被悬浮在反应性溶剂中，并通过化学反应引发。 这些系统在空间和时间上具有自组织的显着特征，远大于单个粒子的量表，这些特征转化为许多尺度上的功能。 这些不同的活性颗粒流体系统先前已被建模。 在这里，调查人员为此类问题提供了一个统一的理论和计算平台，该平台提供了多种好处。 一种常见的数学结构揭示了这些系统如何实现其功能性能，并告知哪些物理和化学特征允许系统对所需属性进行最有效的转向和优化，允许建立一个通用的计算平台，并允许人们合并额外的自由度或对现有的粒子和流体的影响，并预测其后果。 这些进步具有增强有益细菌菌落并破坏有害细菌，修复损坏的细胞功能以及设计具有最佳特性的纳米复合材料的应用。 研究生参与了项目的工作。 数学平台统一了先前的结果，跨越了连续的空间和时间尺度，并在每个描述尺度上识别了一个共同的前阶数学结构以及区分不同活性的各向异性流体之间的低阶结构。 该结构指导分析和算法开发，以理解这些流体系统的显着观察到的行为。 该项目旨在区分对颗粒尺寸，纵横比，浓度和活化能的敏感性，并直接应用于活跃的纳米杆分散剂，肌动蛋白丝凝胶和细菌悬浮液中的敏感性。