Collaborative Research: Actuating and Sensing Objects on a Free Surface

这项合作研究调查了空气-水界面上的浮动颗粒与水波之间的强耦合，这是一个对技术创新有启发的基础性科学问题。自然界中的水面吸引了各种各样的物体，比如寻找食物和配偶的生物，以及污染世界海洋和湖泊的微塑料和石油泄漏。因此，如果能够按需识别和控制这些对象，水面为调查当地生态和清理污染物提供了重要机会。该项目的成果将使人们从根本上了解这类应用所需的物理机制，从为搜索和监视任务在黑暗中定位漂浮物，到为环境保护收集海洋废弃物。此外，私人投资主任将在其所在院校参加各种教育活动，重点是从代表人数不足的群体中招收学生。参与这项研究的学生将接受实验和理论方法方面的培训，并将通过共同建议、虚拟小组会议和演讲参与跨学院的积极合作。这项合作研究的总体目标是从根本上了解漂浮物、表面波和流体之间产生的丰富的动力学相互作用。具体地说，PI团队将在感知和控制流体-流体界面上的对象的背景下发现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，薄液层上的波散和颗粒运动受毛细管力和粘性力控制，而深水表面上的波粒动力学主要受惯性和重力控制。然而，目前还没有一个全面的框架来解决不同尺度界面上表面波和粒子的耦合动力学问题。通过将实验和数学建模相结合，四个PI将研究波粒相互作用的基本原理：在浅水和深水波浪的不同限制下，远程感知(散射波)和漂浮物的驱动(力和扭矩)。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势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.