Flexible kirigami sheets in uniform and disturbed fluid flow

这项研究将调查kirigami片放置在流体流动的行为。近年来，由于简单的二维kirigami图案化的片材在施加力时可以呈现复杂的三维形状，对kirigami的应用（其中在材料片材中形成切割图案）的研究在广泛的研究领域中急剧增加。尽管有大量关于kirigami模式的文献，但它们在流体力学中的应用非常有限。在这项工作中，kirigami片放置在流体流动的行为进行了研究。该项目的更广泛影响扩展到能够设计和部署具有所需几何形状，所需尾流和所需任务的kirigami片材。这种能力将使流动混合，流动控制和水下软机器人的几个应用。这项研究的结果将通过将拟议的研究纳入K-12学生的推广计划并将这项研究纳入课堂，在不同层面上传播。将根据这项工作的成果设计和建造一个厨房展览，使无形的科学现象有形的外行观众，并引发对流体力学研究的浓厚兴趣年轻一代。一个kirigami片放置在流体流动构成不同尺度的流体-结构相互作用（FSI）：切割规模和片材规模。这项工作的初步结果显示了各种各样的三维形状的样品，kirigami片假设当他们被放置在流动。这些结果表明，kirigami片在流动中可以经历静态或动态流诱导的不稳定性作为屈曲或极限环振荡的结果。这个项目首先关注于调查先前设计的kirigami模式放置在流中的行为。然后，该项目的重点是为特定流体应用设计新的kirigami模式，并研究它们在均匀和扰动流中的行为。这项工作的目标将通过进行几个系列的实验来实现，其中kirigami图案片被放置在流体流动。它们的位移将使用高速摄像机跟踪，并将使用气泡图像测速（BIV）量化产生的尾流。该项目的成果将通过为社区中的其他人存档三维形状和尾流来潜在地影响流控制和FSI等领域。该奖项反映了NSF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而被认为值得支持。

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.