Collaborative Research: Large-scale kinetic energy entrainment in the wind turbine array boundary layer - understanding and affecting basic flow physics

这个项目的目标是开发和应用实验和计算工具，通过特别关注大尺度的湍流和动能的垂直通量，来预测和改善风电场的性能，这对大型风力涡轮机阵列具有重要意义。近年来，人们花了很多精力来提高单个风力涡轮机的效率，假设涡轮机前面有一个给定的流入。此外，了解尾迹如何影响下游涡轮机的性能以及多个尾迹的叠加建模也受到了相当大的关注；然而，对于风力涡轮机阵列边界层（WTABL）中大型风力涡轮机阵列如何在更大尺度上与湍流大气边界层相互作用的基本理解相对较少。最近的研究表明，大型风力发电场的一个重要性能限制因素是风力涡轮机上方的气流将动能带入阵列的速度。无论单个风力涡轮机的效率有多高，或者它与上游风力涡轮机的适应程度有多高，最终，动能进入整体阵列的垂直通量在很大程度上决定了从大气流动中提取多少能量。在这个项目中解决的问题旨在更好地理解限制因素和不同尺度的湍流对垂直夹带过程的影响。由此产生的模型可以指导风力涡轮机的布局策略和可能的气流调整，从而提高垂直夹带率。具体而言，将采用风洞实验结合大涡模拟（LES）来解决以下研究问题：(a)发展中的WTABL与完全开发的WTABL之间的本质区别是什么？(b)流向大尺度相干涡对垂直动能夹带的相对贡献是什么？(c)阵列中不同风力涡轮机轮毂高度速度和功率输出的时空相关性是什么？(d)阵列中的风力涡轮机是否有特别的安排，平均来说增加了夹带？(e)是否可以通过修改转子来增加这种夹带来影响大规模流动结构？解决这些问题需要在高度控制和可重复的条件下进行实验的能力，这些条件可以在拟议的风洞实验和计算机模拟中提供。这些数据将与一个大型风电场的相关新现场数据进行比较。更广泛的影响：风能的强劲增长意味着美国和世界上不可忽视的部分土地和近岸表面可能最终被用于大型风力发电场。预测和更好地理解在这种条件下变化的地表和大气耦合的物理过程是一个及时和关键的研究领域。通过项目活动，pi将帮助培训下一代工程师和科学家，使他们具备必要的工具和见解，以帮助美国实现到2030年风能占比达到20%的目标。研究生教育/指导将强调风洞实验、计算机模拟和现场数据分析之间的相互作用。国际（瑞士，西班牙）和工业经验（通用电气）也将在这个项目中强调。招聘和推广将利用这两个pi ？通过波多黎各（NSF-AGEP和LSAMP）的联系，以及JHU的一个复杂系统建模的IGERT，正在努力招募美国西班牙裔研究生。RPI的能源和环境方面的GK-12将利用国家科学基金会的资源对教师进行风能问题的培训。π吗?我们将继续向巴尔的摩的一所高中伸出援手，为高中三年级和四年级学生提供研究经验。

1133800 PI Meneveau/1133993 PI CastilloThe objective of this project is to develop and apply experimental and computational tools for predicting and improving wind farm performance by placing particular attention on large scales of turbulence and vertical fluxes of kinetic energy that are of great significance for large arrays of wind turbines. Much effort has been devoted in recent years to increasing the efficiency of individual wind turbines, assuming a given inflow in front of the turbine. Also, understanding how wakes affect the performance of downstream turbines and modeling superpositions of multiple such wakes has received considerable attention; however, there has been relatively little fundamental understanding of how a large array of wind turbines interacts with the turbulent atmospheric boundary layer at larger scales in the wind turbine array boundary layer (WTABL). Recent research has demonstrated that an important performance-limiting factor for large wind farms is the rate at which kinetic energy can be entrained into the array from the flow aloft, above the wind turbines. No matter how efficient an individual wind turbine is, or how well it can adapt to an upstream wind-turbine, ultimately it is the vertical flux of kinetic energy into the overall array that largely determines how much power can be extracted from the atmospheric flow. The questions addressed in this project aim at better understanding the limiting factors and the effiects of different scales of turbulence on vertical entrainment processes. The resulting models should guide wind turbine placement strategies and possible flow modifications so that vertical entrainment rates can be increased. Specifically, wind tunnel experiments coupled with large-eddy simulations (LES) will be employed to address the following research questions: (a) What are the essential differences between the developing and the fully developed WTABL? (b) What is the relative contribution from streamwise large-scale coherent vortices to vertical entrainment of kinetic energy? (c) What are the space-time correlations of hub-height velocity and power output between different wind turbines in the array? (d) Are there particular arrangements of wind turbines in the array that increase, on average, the entrainment? and (e) Can large-scale flow structures be affected through rotor modifications to increase such entrainment? Addressing such questions requires the ability to experiment under the highly controlled and reproducible conditions that can be afforded in the proposed wind tunnel experiments and computer simulations. The data will be supplemented with comparisons with relevant new field data from a large wind farm. Broader impacts: The robust growth of wind energy implies the possibility that non-negligible portions of theland and near-shore surface of the US and the world may ultimately be used for large wind farms. Predictingand better understanding the physical processes coupling the modified surface and atmosphere under suchconditions is a timely and critical area of research. through project activities the PIs will help train the next generation of engineers and scientists with the necessary tools and insights to help reach the US goal of 20% wind energy by 2030. Graduate education/mentoring will stress the interplay between wind tunnel experimentation, computer simulation and field data analysis. International (Switzerland, Spain) and industrial experiences (General Electric) will also be emphasized in this project. Recruiting and outreach will leverage both PIs? ongoing efforts to recruit US Hispanic graduate students through contacts in Puerto Rico (NSF-AGEP and LSAMP), as well as an IGERT at JHU on modeling complex systems. A GK-12 at RPI on energy and environment will leverage NSF resources in training teachers on wind energy issues. The PI?s ongoing outreach to a Baltimore high-school will be continued, providing research experiences for high-school juniors and seniors.