CAREER: Fluid-Structure-Surface Interactions of Flexible Bodies at the Air-Water Interface

职业：空气-水界面处柔性体的流-固-表面相互作用

• 批准号: 2143263
• 负责人: Banafsheh Seyed-Aghazadeh
• 金额: $ 50.7万
• 依托单位: University of Massachusetts, Dartmouth
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-12-15 至 2026-11-30
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2143263&HistoricalAwards=false
• 关键词: CAREER; Fluid; Structure; Surface; Interactions

Understanding the fundamentals of fluid-structure-surface interactions in underwater flexible bodies (like near surface arrays for energy harvesting or near surface robots) will provide new scientific insights for a broad range of applications. When an underwater flexible body operates near the surface of the fluid, its proximity to the air-water interface can cause free surface deformations. To understand the effect of such deformations on the dynamics of the body, this project will investigate the role played by the coupling between the structural dynamics of the body and the hydrodynamics of its surrounding flow. The design of near surface arrays of energy harvesters is an excellent example of an application where the interaction can be utilized to improve their performance. Moreover, near surface robot designers can benefit from understanding the fundamentals of fluid-structure-surface interactions that can facilitate expanding their mission envelope, ranging from detecting and mapping polluted water spill on the surface, to surveillance of coastal zones, to offshore structural health monitoring. The scientific endeavors in this proposal are integrated with educational activities that will inspire and attract people to engineering and science disciplines, from K-12 schoolchildren in the Southeast Coast of Massachusetts to graduate students through classroom lectures, project-based learning modules, and game-based outreach activities.The goal of this research is to systematically investigate the fluid-structure-surface interactions of flexible films near the air-water interface. Through a set of water tunnel experiments, high speed imaging techniques, and volumetric high-resolution time-resolved particle tracking velocimetry (TR-PTV) measurements, fluid-structure-surface interactions of a flexible film in axial flow placed at varying submerged heights near surface will be studied. Of particular interest are studying the onset of instability, occurrence of any possible flow-induced vibration response, and vortex dynamics in the wake of the film. Comparisons will be made with classical flutter responses observed for flexible films placed in uniform flow, distant from the free surface. Next, an energy-based reduced-order nonlinear model of the near-surface flexible film will be developed by coupling its nonlinear structural dynamics with three-dimensional flow field information, obtained through TR-PTV measurements. A mathematical algorithm incorporating higher-order finite element solution approach of Differential Quadrature Method will be used to solve the fully coupled partial differential equations of motion. The findings are expected to impact the scientific research community and society by providing us with a detailed understanding of fluidelastic behavior of flexible films in proximity of free surface in a wide range of possible operational environments.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.

了解水下柔性物体(如用于能量采集的近水面阵列或近水面机器人)中流体-结构-表面相互作用的基本原理将为广泛的应用提供新的科学见解。当水下柔性物体在流体表面附近操作时，其靠近空气-水界面可能会导致自由表面变形。为了了解这种变形对物体动力学的影响，这个项目将研究物体的结构动力学和其周围流动的流体动力学之间的耦合所起的作用。能量收集器近表面阵列的设计是一个很好的应用实例，其中可以利用交互作用来提高它们的性能。此外，近水面机器人设计者可以从理解流体-结构-表面相互作用的基本原理中受益，这有助于扩大他们的任务范围，从探测和绘制表面污染水溢出的地图，到监测沿海地区，再到近海结构健康监测。这项计划中的科学努力与教育活动相结合，这些活动将激励和吸引人们进入工程和科学学科，从马萨诸塞州东南海岸的K-12小学生到研究生，通过课堂讲座、基于项目的学习模块和基于游戏的推广活动。本研究的目标是系统地研究空气-水界面附近柔性薄膜的流体-结构-表面相互作用。通过一系列水洞实验、高速成像技术和体积高分辨率时间分辨粒子跟踪测速技术(TR-PTV)测量，研究了轴向流中不同淹没高度近地表柔性薄膜的流体-结构-表面相互作用。特别令人感兴趣的是研究不稳定的开始，任何可能的流致振动响应的发生，以及电影尾流中的涡流动力学。将与在远离自由面的均匀流中观察到的柔性薄膜的经典颤振响应进行比较。接下来，通过将其非线性结构动力学与通过TR-PTV测量获得的三维流场信息相耦合，建立了基于能量的近表面柔性薄膜的降阶非线性模型。采用一种结合了微分求积法的高阶有限元求解方法的数学算法来求解完全耦合的偏微分方程组。这些发现预计将影响科学研究社区和社会，使我们能够详细了解自由表面附近柔性薄膜在各种可能的操作环境中的流体弹性行为。这一奖项反映了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。