Nonlinear analysis of flow-induced instabilities of wind turbine blades using theoretical models and supported by experimental data

项目负责人：Yahya modares - sadeghin数字：1437988标题：使用理论模型和实验数据支持的风力涡轮机叶片流动诱导不稳定性的非线性分析机构：马萨诸塞大学阿默斯特分校越来越多地，用于生产电力的风力发电场被选址在海上，以收获这种可再生能源。风力发电场内单个风力涡轮机可以提取的可用能量与涡轮转子叶片的掠面积成正比，这就产生了设计、制造和商业化使用更长更细叶片的强大动力。这种趋势是由经济因素驱动的——海上风力发电场的安装成本大大高于陆上，因此每台安装的风力涡轮机的发电量增加对海上风能的成本效益至关重要。然而，随着叶片变得越来越长，它们变得更容易受到各种流动引起的不稳定性的影响。特别麻烦的不稳定性是由叶片与风的相互作用引起的不必要的叶片振荡或颤振。这种不稳定的行为会导致叶片的灾难性失效。这一限制对海上风力涡轮机的完整性及其可靠运行能力构成了威胁。在目前的研究中，将使用基于非线性分析技术的先进计算模型来研究风力涡轮机叶片的流致不稳定性，以便更好地理解这些不稳定性并为未来风力涡轮机叶片的设计制定指导方针。作为拟议活动的一部分，首席研究员将在北美风能学院（NAWEA）组织一次关于海上风能的会议，针对中学生和高中生制作风力涡轮机的YouTube演示，并就同一主题向当地高中生进行演示。技术描述本研究的目标是为柔性和旋转风力涡轮机叶片开发一个非线性、全耦合的连续流固耦合模型。该模型将用于研究预计将用于未来海岸风力涡轮机的细长叶片的流致不稳定性。风力发电机叶片本质上是一个三维非线性系统。然而，目前风力涡轮机叶片不稳定性分析的方法已经将叶片建模为二维线性系统，以绕过与三维非线性系统建模相关的困难。然而，随着叶片变得越来越长，越来越细，需要更全面的模型是必要的。所提出的柔性和旋转叶片的非线性模型将考虑不同的叶片形状和横截面，以及弯曲和扭转性能。几何、流动相关和流体-结构相互作用的非线性将嵌入到模型中。将进行一系列全面的风洞实验来验证该模型。然后，验证模型将用于提供对风力涡轮机叶片流致不稳定性的基本理解。该方法还可以研究具有长度非均匀性质的柔性结构在与流动的高度非线性相互作用下的非线性不稳定性，从而提供对非线性流固相互作用系统的物理基础的更广泛的理解。关于教育和更广泛的影响，首席研究员将在北美风能学院（NAWEA）组织一次关于海上风能的会议。拓展活动包括开发针对中学生和高中生的关于风力涡轮机的YouTube演示文稿，以及针对当地高中生的相同主题演示。

Principal Investigator: Yahya Modarres-SadeghiNumber: 1437988 Title: Nonlinear analysis of flow-induced instabilities of wind turbine blades using theoretical models and supported by experimental dataInstitution: University of Massachusetts, AmherstIncreasingly, wind farms for the production electricity are being sited off shore to harvest this renewable energy resource. The available energy that individual wind turbines within the wind farm may extract is proportional to the swept area of the turbine rotor blades, creating a powerful incentive to design, manufacture, and commercially use longer and more slender blades. This trend is driven by economics - wind farm installation costs are substantially higher offshore than onshore, and so increased energy production per installed wind turbine is crucial for cost-effective offshore wind energy. However, as blades become longer and more slender, they become more susceptible to various flow induced instabilities. A particularly troublesome instability is the unwanted blade oscillations, or flutter, caused by the interaction of the blade with the wind. This unstable behavior can lead to catastrophic failure of the blades. This limitation poses a threat to the integrity of offshore wind turbines and their ability to reliably operate. In the current research, flow-induced instabilities of wind turbine blades will be studied using advanced computational models based on a technique called nonlinear analysis in order to better understand these instabilities and develop guidelines for the design of future wind turbine blades. As part of the proposed activities, the principal investigator will organize a session at the North American Wind Energy Academy (NAWEA) on Offshore Wind Energy, develop YouTube presentations on wind turbines targeted to middle and high school students, and give demonstrations to local high school students on the same topic. Technical DescriptionThe goal of this research is to develop a nonlinear, fully-coupled continuous fluid-structure interaction model for flexible and rotating wind turbine blades. This model will be used to study flow-induced instabilities for long and slender blades that are anticipated to be used in future shore wind turbines. A wind turbine blade is an inherently three-dimensional and nonlinear system. Nevertheless, current approaches for wind turbine blade instability analysis have modeled the blades as two-dimensional, linear systems in order to bypass the difficulties associated with three-dimensional, nonlinear system modeling. However, as blades become longer and more slender, the need for more comprehensive models is necessary. The proposed nonlinear model for flexible and rotating blades will account for varying blade shapes and cross-sections, as well as bending and torsional properties. Geometric, flow-related and fluid-structure interaction nonlinearities will be embedded into the model. A comprehensive series of wind tunnel experiments will be conducted to validate this model. The validated model will then be used to provide a fundamental understanding of flow-induced instabilities of wind turbine blades. This approach will also enable the study of nonlinear instability of flexible structures with non-uniform properties along their length under highly nonlinear interaction with flow, and thus provide a broader understanding of the physics underlying nonlinear fluid-structure interaction systems. With respect to education and broader impacts, the principal investigator will organize a session at the North American Wind Energy Academy (NAWEA) on Offshore Wind Energy. Outreach activities include development of YouTube presentations on wind turbines targeted to middle and high school students, and demonstrations to local high school students on the same topic.