Toward the Two-Way Coupling between Active Matter and Transport Barriers

在自然和工程系统中，如海洋和工业过程中，不稳定流动在水下颗粒和化学物质的运输和混合中起着重要作用。运输屏障将流动组织成具有大规模连贯结构的不同区域，从而控制被动粒子和物质的混合。例如，可以利用运输障碍来预测石油泄漏的模式。然而，对于这些运输屏障如何影响活性物质的运输和混合，以及反之亦然，我们所知甚少。尽管有证据表明，水生生物，如鱼群和浮游植物，可能影响海洋中的运输，但对活动与运输障碍之间的相互作用缺乏系统的了解。这种理解对于控制非定常流中的活性物质至关重要，并有可能影响从水生生态学到生物启发设计的应用领域。该奖项将支持研究，以提高我们对活性物质和运输障碍之间相互作用的认识。为了揭示输运屏障与活性物质之间的双向耦合，PI将在电磁驱动的实验室流中进行光导盐水虾（Artemia salina）的实验。研究计划围绕两个目标展开：(1)确定与活性物质与大尺度输运屏障耦合最相关的无维群，并划分其所跨越的相应高维空间；(2)了解活性物质中的小尺度尺度如何通过尺度渗透来改变大尺度尺度的输运屏障。本研究结果将为现实世界中可实施的活性物质控制策略铺平道路。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。

Unsteady flows in natural and engineering systems, such as in the ocean and in industrial processes, play a fundamental role in the transport and mixing of submerged particles and chemical substances. Transport barriers organize flows into distinct regions with large scale coherent structures, and, thus, control the mixing of passive particles and substances. For example, transport barriers can be exploited to predict oil spill patterns. However, less is known about how these transport barriers affect the transport and mixing of active matter and vice-versa. Despite evidence that aquatic organisms, such as fish schools and phytoplankton, could affect transport in the ocean, a systematic understanding of the interplay between activity and transport barriers is lacking. Such understanding is crucial for controlling active matter in unsteady flows, with the potential to impact application areas ranging from aquatic ecology to bio-inspired designs. This award will support research to advance our knowledge of the interplay between active matter and transport barriers. In order to reveal the two-way coupling between transport barriers and active matter, the PI will conduct experiments in electromagnetically driven laboratory flows with light-guided brine shrimp (Artemia salina). The research plan is structured around two aims: (1) to determine the non-dimensional groups that are most relevant in the coupling of active matter and large scale transport barriers, and divide the corresponding high dimensional space spanned by the non-dimensional groups; (2) to understand how small length scale in active matter percolate through scales to modify the large length scale transport barriers. The results of this research will pave the way for implementable control strategies of active matter in real-world scenarios.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.