Flexible kirigami sheets in uniform and disturbed fluid flow

本研究将探讨基里伽米薄片在流体流动中的行为。近年来，由于简单的二维kirigami图案片在施加力时可以呈现复杂的三维形状，因此对kirigami的应用研究在广泛的研究领域中急剧增加。尽管已有大量关于基里伽美模式的文献，但它们在流体力学中的应用却极为有限。本文研究了基里格米薄片在流体流动中的行为。该项目更广泛的影响延伸到能够设计和部署具有理想几何形状、理想尾流和理想任务的kirigami板。这种能力将在流动混合、流动控制和水下软机器人等领域得到广泛应用。本研究的结果将通过将拟议的研究整合到K-12学生的外展计划中，并通过将本研究纳入课堂，在不同层次上传播。在此基础上，我们将设计和建造一个画廊展览，将不可见的科学现象呈现给非专业观众，并激发年轻一代对流体力学研究的浓厚兴趣。放置在流体中的基利伽米薄片在不同的尺度上构成了流体结构相互作用（FSI）：切割尺度和薄片尺度。这项工作的初步结果显示了基利伽米薄片在流动时所呈现的各种三维形状的样品。这些结果表明，基利格米板在流动中会由于屈曲或极限环振荡而发生静态或动态的流致失稳。该项目首先侧重于研究先前设计的kirigami模式在流中的行为。然后，该项目侧重于为流体特定应用设计新的kirigami图案，并研究它们在均匀和扰动流动中的行为。这项工作的目标将通过进行几个系列的实验来实现，在这些实验中，基里伽米图案的薄片被放置在流体中。它们的位移将使用高速摄像机进行跟踪，由此产生的尾迹将使用气泡图像测速（BIV）进行量化。该项目的结果将通过将三维形状和尾迹存档，为社区中的其他人潜在地影响诸如流量控制和FSI等领域。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。

The research will investigate the behavior of kirigami sheets placed in fluid flow. Research into applications of kirigami, wherein patterns of cuts are made in a sheet of material, has increased dramatically across a wide range of research areas in recent years due to the complex three-dimensional shapes that simple two-dimensional kirigami patterned sheets can assume when forces are applied on them. Despite the significant existing literature on kirigami patterns, their use in fluid mechanics has been extremely limited. In this work, the behavior of kirigami sheets placed in fluid flow is investigated. The broader impacts of this project extend to being able to design and deploy kirigami sheets with desired geometries, desired wakes, and for desired tasks. This ability will enable several applications in flow mixing, flow control, and underwater soft robotics. The findings of this research will be disseminated at different levels by integrating the proposed research into the outreach programs for K-12 students and by incorporating this research into classes. A galley exhibition will be designed and built based on the results of this work to render the invisible scientific phenomena tangible for a lay audience, and to spark deep interest in fluid mechanics research for younger generations.A kirigami sheet placed in fluid flow constitutes fluid-structure interactions (FSI) at different scales: the cut-scale and the sheet-scale. The preliminary results of this work have shown samples of a variety of three-dimensional shapes that kirigami sheets assume when they are placed in flow. These results show that kirigami sheets in flow can undergo static or dynamic flow-induced instabilities as a result of buckling or limit cycle oscillations. This project first focuses on investigating the behavior of previously designed kirigami patterns placed in flow. Then the project focuses on designing new kirigami patterns for fluid-specific applications and studying their behavior in uniform and disturbed flows. The goals of this work will be achieved by conducting several series of experiments where kirigami-patterned sheets are placed in fluid flow. Their displacements will be tracked using high speed cameras, and the resulting wakes will be quantified using bubble image velocimetry (BIV). The results of this project will potentially impact areas such as flow control and FSI by archiving the three-dimensional shapes and wakes for others in the community.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.