Collaborative Research: Actuating and Sensing Objects on a Free Surface

本合作研究探讨了空气-水界面悬浮粒子与水波之间的强耦合，这是一个具有技术创新灵感的基础科学问题。自然界的水面吸引着各种各样的物体，比如寻找食物和配偶的生物有机体，以及污染世界海洋和湖泊的微塑料和石油泄漏。因此，水面提供了一个重要的机会来调查当地的生态和清洁污染物，如果一个人可以识别和控制这些对象按需。该项目的成果将提供对这些应用所需的物理机制的基本理解，这些应用范围从在黑暗中定位漂浮物进行搜索和监视任务，到收集海洋垃圾进行环境保护。此外，这些学生还将在其所在院校参加各种教育活动，重点是招收代表性不足的群体的学生。参与这项研究的学生将接受实验和理论方法的培训，并通过共同建议、虚拟小组会议和报告等方式积极参与各研究所的合作。这项合作研究的总体目标是获得对漂浮物体、表面波和流体流动之间产生的丰富动态相互作用的基本理解。具体来说，PI团队将揭示在流体-流体界面感知和控制物体的背景下复杂的粒子波相互作用。根据系统的相关长度尺度，有不同类型的水动力相互作用占主导地位。例如，在稀薄的液体层上，波的弥散和粒子的运动是由毛细力和粘性力控制的，而深水表面上的波粒动力学主要是由惯性和重力控制的。然而，目前还没有一个全面的框架可以解决界面上不同尺度表面波和粒子的耦合动力学问题。通过结合实验和数学建模，四个pi将研究波粒相互作用的基本原理：在浅水波和深水波的不同限制下，远程感知（散射波）和驱动（力和扭矩）漂浮物。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。

This collaborative research investigates the strong coupling between floating particles at the air-water interface and water waves, which is a fundamental scientific problem with inspiration for technological innovation. The water surface in nature attracts all sorts of objects, such as biological organisms in search of food and mates, as well as microplastics and oil spills polluting the world's oceans and lakes. Thus, the water surface provides an important opportunity to survey the local ecology and clean the pollutants if one can identify and control these objects on-demand. The outcomes of this project will provide fundamental understanding of physical mechanisms necessary for such applications, which range from locating floating objects in darkness for search and surveillance missions, to collecting marine debris for environmental protection. In addition, the PIs will participate in various educational activities at their home institutions with a focus on recruiting students from under-represented groups. The students participating in this research will be trained in both experimental and theoretical approaches and will engage in active collaboration across institutes through co-advising, virtual group meetings, and presentations. The overall objective of this collaborative research is to gain fundamental understanding of rich dynamical interactions that arise between the floating objects, surface waves and fluid flows. Specifically, the PI team will uncover complex particle-wave interactions in the context of sensing and controlling objects at the fluid-fluid interface. There are different types of hydrodynamic interactions that dominate depending on the relevant length scale of the system. For example, wave dispersion and particle movement on a thin liquid layer are governed by capillary and viscous forces, while the wave-particle dynamics on the deep water surface is governed primarily by inertia and gravity. However, there is no comprehensive framework at present that can resolve the coupled dynamics of the surface waves and particles at the interface across different scales. By combining experiments and mathematical modeling, the four PIs will investigate the fundamentals of wave-particle interactions: sensing (scattered waves) and actuation (force and torque) of floating objects remotely, in the distinct limits of shallow and deep water waves.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.