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

自然和工程系统中的非定常流动，例如海洋和工业过程中的非定常流动，在水下颗粒和化学物质的运输和混合中起着重要作用。输运障碍组织成具有大尺度相干结构的不同区域的流动，并因此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模式。然而，很少有人知道这些运输障碍如何影响运输和混合的活性物质，反之亦然。尽管有证据表明，鱼群和浮游植物等水生生物可能影响海洋中的迁移，但对活动与迁移障碍之间的相互作用缺乏系统的了解。这种理解对于控制不稳定流中的活性物质至关重要，有可能影响从水生生态到生物设计的应用领域。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。为了揭示传输障碍和活性物质之间的双向耦合，PI将在电磁驱动的实验室流中使用光导卤虫（卤虫）进行实验。研究计划围绕两个目标进行：（1）确定在活动物质和大尺度传输障碍耦合中最相关的无量纲组，并划分相应的无量纲组所跨越的高维空间;（2）了解活动物质中的小长度尺度如何渗透通过尺度来修改大长度尺度传输障碍。这项研究的结果将铺平道路，在现实世界的情况下，积极物质的可实施的控制策略。这个奖项反映了NSF的法定使命，并已被认为是值得通过使用基金会的智力价值和更广泛的影响审查标准进行评估的支持。

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.