CAREER: Hydrodynamics of Adaptive Lifting Surfaces in Unsteady Flows: An Integrated Experimental and Analytical Study

非定常流场在许多水下应用中是常见的，如在高海况、螺旋桨尾迹、合作游泳期间或潮汐和波浪中。在这样的环境中，对于传统的自主水下机器人(AUV)来说，悬停、保持站位或执行任何其他动态机动都变得极其困难，因为它们通常在固定的工作范围内使用刚性水翼设计。然而，水上游泳者可以适当地改变他们的鳍和尾巴，以控制所有位置和方向的不稳定力量。工程师们可以设计具有高度机动性的下一代AUV，其仿生变形水翼可以模仿这种性能。但一个主要的瓶颈是缺乏控制这种变形升力面的流体-结构相互作用的非定常流体动力学知识。因此，本项目的主要目的是对自适应升力表面的非定常流体动力学有一个深入的了解。该项目还将在所有级别的学生中促进海洋流体动力学和水下机器人的高级教育，包括在奥兰多科学中心和奥兰治县公共图书馆的推广活动。该计划的目标是开发新的研究和教育范式，揭示和推广变形升力表面的物理学，以在遇到瞬时尾流流入条件时优化其性能。提出了一种实验与分析相结合的方法来研究这种非定常流动中自适应升力面的非线性流固耦合问题。中心假设是，形状变形可以通过选择性地调整瞬时尾流中的水弹性响应，来动态平衡这种自适应升力面上的非定常载荷。具体目标是：(A)揭示自适应水下升力面在一系列非定常流动中复杂的非线性FSI响应；(B)通过三维流场和表面压力的时间分辨实现，破译涡度动力学和表面压力的时空特征；(C)发现动态变形升力面受到周期性涡动扰动引起的空间变化流入时，上述非线性FSI响应的变化；(D)通过显著推进现有的基于潜在流量的框架来开发分析模型。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。

Unsteady flow fields are common in many underwater applications, such as during high sea conditions, in a propeller wake, during cooperative swimming or during tides, and waves. In such environments, hovering, station keeping, or performing any other dynamic maneuvers become extremely difficult for traditional autonomous underwater vehicles (AUVs) because they are typically designed with rigid hydrofoils within a fixed operational envelope. However, aquatic swimmers can aptly morph their fins and tails to control unsteady forces across all positions and orientations. Engineers can design highly maneuverable next-generation AUVs with bio-inspired morphing hydrofoils which can mimic such performance. But a major bottleneck has been the lack of knowledge of unsteady hydrodynamics that govern the fluid-structure interaction of such morphing lifting surfaces. Therefore, the principal aim of this project is to provide a deep understanding of the unsteady hydrodynamics of adaptive lifting surfaces. This project will also promote advanced education of marine hydrodynamics and underwater robotics amongst students at all level, including outreach activities at the Orlando Science Center and the Orange County Public Library.The goal of this proposal is to develop new research and educational paradigm that will reveal and generalize the physics of morphing lifting surfaces to optimize its performance while encountering transient wake-inflow conditions. An integrated experimental and analytical approach is proposed to study the non-linear fluid-structure interaction (FSI) of adaptive lifting surfaces in such unsteady flows. The central hypothesis is that shape morphing can dynamically balance the unsteady loads on such adaptive lifting surfaces by selectively tuning the hydro-elastic response in a transient wake-inflow. The specific objectives are: (a) Unravel the complex non-linear FSI response of adaptive underwater lifting surfaces in a range of unsteady flows; (b) Decipher the spatial and temporal features of the vorticity dynamics and surface pressure through the time-resolved realization of the 3D flow-field and surface pressure; (c) Discover the changes in the above non-linear FSI response when the dynamically deforming lifting surface is subjected to a spatially varying inflow caused by periodic vortical disturbances; (d) Develop analytical models by significantly advancing the existing potential-flow-based framework.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.