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

2019年，风能成为美国最大的可再生能源，预计在十年内，风能将在美国所有发电量中占据相当大的比例。大型风力涡轮机的引入被认为是一个重要的方向，因为它们可以导致发电量的增加。然而，风力涡轮机可能不是所有风速和地点(如建筑屋顶)的最佳解决方案。作为替代方案，将研究一套可以在小足迹和低风速下使用的压电式收割机。这些收割机代表了一个振荡系统的例子，在这个系统中，结构构件之间的耦合由流体力主导，这些流体力是在气流中运动时产生的。其他具有类似流体(气动)耦合的振荡系统包括涡轮发电机、压缩机和涡轮风扇中的旋转叶片。通过GOALI学术联络机会奖的支持，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库。一个显著的影响预计将是我们对涉及流体-结构-机电相互作用的系统的非线性行为的理解的进步。通过对这些系统可行性的实验论证，人们有望设计和制造用于建筑系统和系泊无人驾驶车辆系统的压电能量收集器。这项工作将迎来新一代研究人员，他们将接受培训，使用适合于研究能量利用系统的非线性动力学的多学科工具。一个来自学术界和工业界的研究团队将在非线性振子、气动弹性、实验流体力学和活性材料的先前工作的基础上，追求对气动耦合压电振荡器的基本理解的共同目标。该小组将进行原创的风洞实验，以了解薄翼型振荡器阵列和钝体振荡器阵列的流动诱导振荡，并研究系统响应中各种流动的能量分布。根据实验结果并以行业经验为指导，将进行建模和模拟工作，以揭示非线性现象和非线性不稳定性，包括Hopf不稳定性。在根本方面，结果之一将是加深对具有气动耦合的耦合振子的行为、不同流动和振子构型的这种耦合的性质以及相关的非线性流体-结构相互作用的理解。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。

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.