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.

这项研究将为活性流体的设计和控制提供理论框架。活跃的流体是由能量驱动的，能量是在组成流体的粒子的小范围内添加的。例如，我们细胞中的胞质之所以流动，是因为分子马达消耗储存能量的ATP分子，并利用这种能量使刚性生物聚合物相互滑动。这种滑动运动诱导了可用于细胞爬行或细胞内生物材料运输的流动。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控设备。如果要使活性流体在医学或工业上有实际用途，了解它们的流体动力学性质是至关重要的。这项研究的重点是对活动流体在受到外部驱动流动(如泵驱动的流动)时的流动进行数学建模。将理论计算结果与实验结果进行比较，以确定控制主动流性质的参数。这项研究将为本科生和研究生的科学培养提供支持。PIS将通过领导力联盟暑期研究早期识别计划，指导工程和物理科学领域历史上代表性不足的本科生。与这项工作相关的主题将整合到工程和物理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，即活性非极丝足够稀薄，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被用来研究二维活性凝胶中受Couette、Poiseuille和Taylor-Couette类型外流影响的活动驱动流动转变。模拟将被用来探索在盖子驱动的空腔流动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、扭矩和自发运动。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。