CAREER: Unveiling the Stability, Rheology, and Topology of Active Fluids

职业生涯：揭示活性流体的稳定性、流变性和拓扑结构

• 批准号: 1943759
• 负责人: Tong Gao
• 金额: $ 50万
• 依托单位: Michigan State University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-08-15 至 2025-07-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1943759&HistoricalAwards=false
• 关键词: CAREER; Unveiling; Stability; Rheology; Topology

This CAREER award involves emerging field of active fluids, which are a new class of liquid materials made up of densely packed suspensions of particles that can propel themselves by converting energy from locally available fuel into locomotion. Active fluids hold great potential for the development of new materials and products, but realizing this potential requires a quantitative understanding of the unusual material properties and transport mechanisms that these fluids exhibit, which can be much different than the properties of suspensions of inert particles. This project will combine theoretical analysis and numerical simulations to build a holistic computation framework for modeling, analysis, and control of active fluids in complex microfluidic environments. The project will provide undergraduate and graduate student training, create K-12 outreach opportunities, and support the development of a Virtual Reality package that will help interpret research results and enrich classroom teaching. The Virtual Reality package and demos will be available online to the general public, along with some of the open-source computation codes developed in the project, which will benefit both students and researchers in applied science and engineering.The physical properties of active fluids are fundamentally different from those of classical equilibrium systems. When suspended in a liquid, motile microparticles exert stresses on the ambient flows, which acts as a coupling medium for generating large-scale, unsteady collective dynamics. These concentrated systems often show common features, including ordering transition, fluctuating density, and force generation. The research in this project will take the next engineering step of learning how to manipulate active fluids by taking full advantage of their collective behaviors. The project consists of four research thrusts: (1) Develop a hybrid algorithm that combines penetration-free Stokesian dynamics particle simulations and coarse-grained active liquid crystal models; (2) Study the hydrodynamic instabilities and coherent flows; (3) Investigate non-equilibrium rheological properties and topological structures; and (4) Design active-liquid metamaterials for novel engineering applications. The hybrid algorithm will follow a bottom-up multiscale approach. The microscale discrete particle dynamics will be used to construct continuum kinetic models and new "polar" active liquid crystal models. The computational framework will permit researchers and practitioners to control active fluids by adjusting particle activity and interactions at the microscale, and by controlling and guiding constrained coherent flows at the macroscale. The numerical studies, together with supporting experimental verifications, will lead to quantitative understandings of the linkages between dynamics across scales, and possibly to new engineering devices for transporting fluids and particles.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.

本次CAREER奖涉及活性流体的新兴领域，这是一种新型液体材料，由密集堆积的颗粒悬浮液组成，可以通过将当地可用燃料的能量转化为运动来推动自己。活性流体具有开发新材料和新产品的巨大潜力，但要实现这一潜力，需要对这些流体所表现出的不寻常的材料特性和传输机制进行定量理解，这些特性可能与惰性颗粒悬浮液的特性大不相同。本项目将结合理论分析与数值模拟，为复杂微流控环境中主动流体的建模、分析与控制建立一个整体的计算框架。该项目将提供本科生和研究生培训，创造K-12外展机会，并支持虚拟现实包的开发，这将有助于解释研究成果和丰富课堂教学。虚拟现实包和演示将在网上提供给公众，以及项目中开发的一些开源计算代码，这将使应用科学和工程领域的学生和研究人员受益。活性流体的物理性质与经典平衡系统的物理性质有着根本的不同。当运动微粒悬浮在液体中时，它们会对周围的流体施加应力，从而作为耦合介质产生大规模的非定常集体动力学。这些集中的系统通常表现出共同的特征，包括有序跃迁、密度波动和力的产生。该项目的研究将采取下一个工程步骤，学习如何通过充分利用它们的集体行为来操纵活性流体。该项目包括四个研究重点：(1)开发一种结合无穿透Stokesian动力学粒子模拟和粗粒度主动液晶模型的混合算法；(2)研究水动力不稳定性和相干流动；(3)研究非平衡流变性能和拓扑结构；(4)为新的工程应用设计活性液体超材料。混合算法将遵循自下而上的多尺度方法。微观尺度的离散粒子动力学将用于构建连续动力学模型和新的“极性”活性液晶模型。计算框架将允许研究人员和实践者通过在微观尺度上调整粒子活动和相互作用，以及在宏观尺度上控制和引导受约束的连贯流动来控制活性流体。数值研究，连同支持性的实验验证，将导致对跨尺度动力学之间联系的定量理解，并可能产生用于输送流体和颗粒的新工程装置。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

项目成果

Q -tensor model for undulatory swimming in lyotropic liquid crystal polymers

溶致液晶聚合物中波动游动的 Q 张量模型

• DOI: 10.1017/jfm.2021.531
• 发表时间: 2021
• 期刊: Journal of Fluid Mechanics
• 影响因子: 3.7
• 作者: Lin, Zhaowu;Chen, Sheng;Gao, Tong
• 通讯作者: Gao, Tong

Anisotropic swimming and reorientation of an undulatory microswimmer in liquid-crystalline polymers

液晶聚合物中波动微型游泳器的各向异性游泳和重新定向

• 发表时间: 2022
• 期刊: Journal of fluid mechanics
• 影响因子: 3.7
• 作者: Lin, Zhaowu;Yu, Zhaosheng;Li, Jinxing;Gao, Tong
• 通讯作者: Gao, Tong

Hydrodynamic instabilities of activity-balanced binary suspensions

活性平衡二元悬浮液的流体动力学不稳定性

• DOI: 10.1103/physrevfluids.7.063101
• 发表时间: 2022
• 期刊: Physical Review Fluids
• 影响因子: 2.7
• 作者: Palmer, Bryce;Yan, Wen;Gao, Tong
• 通讯作者: Gao, Tong

Understanding topological defects in fluidized dry active nematics

了解流化干活性向列相的拓扑缺陷

• DOI: 10.1039/d1sm01405f
• 发表时间: 2022
• 期刊: Soft Matter
• 影响因子: 3.4
• 作者: Palmer, Bryce;Chen, Sheng;Govan, Patrick;Yan, Wen;Gao, Tong
• 通讯作者: Gao, Tong

Scaling law of Brownian rotation in dense hard-rod suspensions

稠密硬棒悬浮液中布朗旋转的标度定律

• DOI: 10.1103/physreve.102.012608
• 发表时间: 2020
• 期刊: Physical Review E
• 影响因子: 2.4
• 作者: Chen, Sheng;Yan, Wen;Gao, Tong
• 通讯作者: Gao, Tong