Active Fluids in Externally Driven Flows

外部驱动流中的活性流体

• 批准号: 2227361
• 负责人: Thomas Powers
• 金额: $ 42.68万
• 依托单位: Brown University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-09-01 至 2025-08-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2227361&HistoricalAwards=false
• 关键词: Active; Fluids; Externally; Driven; Flows

This research will develop the theoretical framework for the design and control of active fluids. Active fluids are driven by energy which is added at the small scale of the particles that make up the fluid. For example, the cytosol in our cells flows because molecular motors consume energy-storing ATP molecules and use this energy to slide rigid biopolymers past each other. This sliding motion induces flows that can be used for cell crawling or the transport of biological materials within the cell. There is currently great interest in developing artificial active matter systems, such as a microfluidic device which pumps itself. Understanding the hydrodynamic properties of active fluids is essential if they are ever to be of practical use in medicine or industry. The focus of this research is to mathematically model the flow of an active fluid when it is subject to an externally driven flow, such as the flow driven by a pump. The results of theoretical calculations will be compared with experiments to determine the parameters that control the nature of active flow. This research will support the scientific training of undergraduate and graduate students. The PIs will mentor undergraduates from historically underrepresented groups in engineering and physical science through the Leadership Alliance Summer Research Early Identification Program. Topics related to this work will be integrated into undergraduate and graduate courses in engineering and physics. There are very few studies of active matter subject to external flows. The goal of this research is to study the fluid dynamics of active gels, i.e. active apolar filaments that are sufficiently dilute that they tend not to spontaneously align and form a liquid crystalline phase. Linear stability analysis and numerical computation will be used to study the activity-driven flow transitions in active gels in two dimensions subject to external flows of Couette, Poiseuille, and Taylor-Couette types. Simulations will be used to explore the effect of confinement on active gels in lid-driven cavity flow. Finally, three-dimensional channel flows of active gels will be studied, as well as the drag forces and torques and spontaneous motion of objects in an active gel.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.

这项研究将开发主动流体设计和控制的理论框架。活性流体由构成流体的小颗粒粒子添加的能量驱动。例如，我们细胞中的细胞质之所以流动，是因为分子马达消耗能量储存的 ATP 分子，并利用这种能量使刚性生物聚合物彼此滑动。这种滑动运动引起的流动可用于细胞爬行或细胞内生物材料的运输。目前人们对开发人工活性物质系统非常感兴趣，例如自动泵送的微流体装置。如果活性流体要在医学或工业中实际应用，那么了解活性流体的流体动力学特性至关重要。这项研究的重点是对活性流体在受到外部驱动流（例如由泵驱动的流）时的流动进行数学建模。理论计算的结果将与实验进行比较，以确定控制主动流性质的参数。这项研究将支持本科生和研究生的科学训练。 PI 将通过领导力联盟夏季研究早期识别计划来指导工程和物理科学领域历史上代表性不足的群体的本科生。与这项工作相关的主题将被纳入工程和物理学的本科生和研究生课程中。关于受外部流动影响的活性物质的研究很少。这项研究的目的是研究活性凝胶的流体动力学，即活性非极性丝，它们被充分稀释，以至于它们不会自发排列并形成液晶相。线性稳定性分析和数值计算将用于研究受 Couette、Poiseuille 和 Taylor-Couette 类型外部流动影响的二维活性凝胶中活动驱动的流动转变。模拟将用于探索在盖驱动腔流中限制对活性凝胶的影响。最后，将研究活性凝胶的三维通道流动，以及活性凝胶中物体的阻力和扭矩以及自发运动。该奖项反映了 NSF 的法定使命，并通过使用基金会的评估进行评估，认为值得支持。智力价值和更广泛的影响审查标准。