NSF-BSF: A Self-sustaining Wind Energy Extraction Technique (SWEET) Using Multi-level Control Design Methods

基于振荡箔的集风系统利用极限循环振荡(或约束颤振)现象来发电，这些系统能够产生足够的电力来支持平均每月900千瓦时的家庭用电量。在这个项目中，研究人员的目标是解决这种可再生能源技术最具挑战性的方面之一，在这方面，在理解积极保持极限环振荡并在现实的、时变的操作环境中实现持续发电的方法方面仍然存在重大差距，而FOIL在自然界中将遇到这种情况。为此，该项目将研究新的主动流量控制方法，这些方法被证明在现实运行环境中能够很好地控制颤振诱导的风能提取特性。为了获得尽可能高的净功率输出，项目研究人员将使用嵌入在箔片中的低辅助功率执行器，这在传统的流量控制应用中是已知有效的。建议的闭环主动流量控制系统将使用高保真计算流体力学模拟和实验风洞测试进行测试和改进。开发的主动流量控制方法可以成功地应用于风能提取技术的进一步优化研究，与传统的风力机设计相比，可以提供一些潜在的好处(包括低噪声、低风速要求和紧凑性)。该项目进一步提供了提高基于振荡箔片的风力收集系统的实用性能的潜力，从而使它们更易于广泛实施。该项目通过创建一个多学科研究和开发小组，将研究和教育整合在一起，由航空航天工程和工程物理本科生和研究生团队合作，为风能收集系统基于物理的控制方法开发概念设计。项目小组组长在提名学生参加该项目时，将遵循促进代表不足群体机会均等的传统。为了完成拟议的调查，将首先为基于振荡箔的风能收集系统建立面向控制的降阶数学模型，其中包括发电系统、箔安装的流量执行器、流体流动动力学和振荡箔的气动弹性效应的详细动态模型。然后，将开发和严格分析新的非线性、闭环主动流动控制方法，这些方法被证明可以影响翼面流体的速度/压力场，使得振动翼在广泛的风速和意外的阵风范围内获得最大的能量。该项目将利用详细的数学分析方法来研究和严格量化新开发的主动流动控制系统能够可靠地维持箔片振荡的操作条件范围。这项研究项目的另一个目标是开发实际可实现的反馈控制设计，不需要函数逼近器，最小的计算复杂性，以及很少的传感器测量。基于箔片的振荡式集风系统具有与旋转式风力涡轮机系统相当的性能水平，同时受益于低风速环境。为了设计可靠和实用的基于振动箔的能量发电系统，必须对流固耦合动力学进行详细的数学建模和主动控制，并对其有清楚的了解。该项目的实验验证方面将与以色列海法理工学院的Oksana Stalnov博士合作，使用他们的风洞设备。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。

Oscillating foil-based wind harvesting systems utilize the phenomenon of limit-cycle oscillation (or constrained flutter) to generate power, and these systems are capable of generating enough power to support the average household electricity usage of 900 KWH per month. In this project, researchers aim to address one of the most challenging aspects of this renewable energy technology, in which significant gaps still exist in understanding methods to actively maintain limit cycle oscillations and achieve continual power generation in the realistic, time-varying operational environments that foils would encounter in Nature. To this end, the project will investigate new active flow control methods, which are shown to achieve well-controlled flutter-induced wind energy extraction characteristics in realistic operating environments. To achieve the highest possible net power output, the project researchers will employ low-auxiliary power actuators embedded in the foil, which are known to be effective in conventional flow control applications. The proposed closed-loop active flow control systems will be tested and refined using high-fidelity computational fluid dynamics simulations and experimental wind tunnel tests. The developed active flow control methods could be successfully employed in further optimization studies of the wind energy extraction technology, which could offer several potential benefits (including low noise, low wind speed requirements, and compactness), compared to the traditional wind turbine designs. The project further offers the potential to enhance the practical performance of oscillating foil-based wind harvesting systems, thus making them more amenable to widespread implementation. The project integrates research and education through the creation of a multidisciplinary research and development group, in which aerospace engineering and engineering physics undergraduate and graduate students work in teams to develop conceptual designs for physics-based control methods for wind energy harvesting systems. Project team leaders will follow the tradition of promoting equal opportunities for underrepresented groups when nominating students for the project.To perform the proposed investigations, control-oriented, reduced-order mathematical models will first be formulated for oscillating foil-based wind energy harvesting systems, which incorporate detailed dynamic models of the power generation system, foil-mounted flow actuators, fluid flow dynamics, and the aeroelastic effects of the oscillating foil. New methods of nonlinear, closed-loop active flow control will then be developed and rigorously analyzed, which are proven to influence the foil-surface fluid flow velocity/pressure field in such a way that the energy harvested by the oscillating foil is maximized over a wide range of wind velocities and unexpected gusts. The project will utilize detailed mathematical analytical methods to investigate and rigorously quantify the range of operating conditions within which the newly developed active flow control systems can reliably maintain foil oscillations. An additional aim of this research project is to develop feedback control designs that are practically implementable, requiring no function approximators, minimal computational complexity, and few sensor measurements. Oscillating foil-based wind harvesting systems promise performance levels comparable to that of rotary wind turbine systems, while benefiting from low wind-speed environments. To design reliable and practical oscillating foil-based energy generation systems, detailed mathematical modeling and active control of the fluid-structure interaction dynamics must be rigorously investigated and clearly understood. The experimental validation aspect of the project will be performed in collaboration with Dr. Oksana Stalnov, of the Technion-Israel Institute of Technology in Haifa, Israel, using their wind tunnel facility.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.