GOALI/Collaborative Research: Nonlinear Energy Dynamics of Aerodynamically Coupled Oscillators

2019年，风能成为美国发电量最大的可再生能源，预计在十年内，风能将占美国所有发电量的重要组成部分。大型风力涡轮机的引入被认为是一个重要的方向，因为它们可以增加发电量。然而，风力涡轮机可能不是所有风速和建筑屋顶等位置的最佳解决方案。作为一种替代方案，一套可以在小足迹和低风速下使用的压电收割机将被研究。这些收割机代表了振荡系统的一个例子，在振荡系统中，结构部件之间的耦合是由气流运动过程中产生的流体力主导的。其他具有类似流体（气动）耦合的振荡系统包括涡轮发电机、压气机和涡轮风扇中的旋转叶片。透过这项“与工业界学术联络资助机会”（GOALI）的支持，我们将继续进行基础研究，以发展和扩展空气动力耦合振荡器的知识基础。一个显著的影响预计是我们对涉及流体-结构-机电相互作用的系统的非线性行为的理解的进步。通过实验证明这些系统的可行性，预计人们可以设计和制造用于建筑系统和系留无人驾驶车辆系统的压电能量采集器。这项工作将迎来新一代的研究人员训练使用多学科的工具，适合研究非线性动力学的能源利用系统。基于之前在非线性振荡器、气动弹性、实验流体力学和活性材料方面的努力，一个来自学术界和工业界的研究人员团队将追求对空气动力耦合压电弹性振荡器的基本理解的共同目标。该小组将进行原始风洞实验，以了解薄翼型振子阵列和钝体振子阵列的流动诱导振荡，并研究系统响应在各种流动中的能量分布。根据实验结果和行业经验，将进行建模和仿真工作，以揭示非线性现象和非线性不稳定性，包括Hopf不稳定性。在基础方面，结果之一将是加强对气动耦合耦合振子行为的理解，不同流动和振子配置的耦合性质，以及相关的非线性流固耦合。在应用方面，这项工作将产生基于流线型和钝体振荡器的能量利用阵列的性能表征工具。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。

Wind energy became the largest renewable energy generated in the US in 2019, and this energy is projected to be a signification portion of all generated electrical energy in the nation within a decade. The introduction of large wind turbines has been considered to be an important direction, as they can result in an increase in generated power. However, wind turbines may not be the best solution for all wind speeds and locations such as building roof-tops. As an alternative, a set of piezoelectric harvesters, which can be used with small foot-prints and at low wind speeds will be studied. These harvesters represent an example of an oscillatory system, in which the coupling between the structural members is dominated by fluid forces that are generated during motions through an air flow. Other oscillatory systems with similar fluid (aerodynamic) coupling include rotating blades in turbine generators, compressors, and turbo fans. Through support of this Grant Opportunity for Academic Liaison with Industry (GOALI) award, fundamental studies will be pursued to develop and extend the knowledge base on aerodynamically coupled oscillators. A salient impact is expected to be the advancement of our understanding of the nonlinear behavior of systems involving fluid-structural-electromechanical interactions. Through experimental demonstrations of the feasibility of these systems, it is expected that one can design and build piezoelectric energy harvesters for use in building systems and tethered unmanned vehicle systems. This work will usher in a new generation of researchers trained to use multi-disciplinary tools suited for study of nonlinear dynamics of energy harnessing systems.Building on prior efforts on nonlinear oscillators, aeroelasticity, experimental fluid mechanics, and active materials, a team of researchers from academia and industry will pursue the common goal of developing a fundamental understanding of aerodynamically coupled piezoelastic oscillators. The group will conduct original wind tunnel experiments to understand flow induced oscillations of thin airfoil oscillator arrays and bluff body oscillator arrays and study the energy distribution in the system responses across a variety of flows. Informed by experimental findings and guided by industry experience, modeling and simulation efforts will be undertaken to uncover nonlinear phenomena and nonlinear instabilities including Hopf instabilities. On the fundamental side, one of the outcomes will be an enhanced understanding of the behavior of the coupled oscillators with aerodynamic coupling, the nature of this coupling for different flows and oscillator configurations, and the associated nonlinear fluid-structure interactions. On the application side, this work will result in performance characterization tools for energy harnessing arrays based on streamlined and bluff body oscillators.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.