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

1133800 PI Meneveau/1133993 PI Castillo该项目的目标是开发和应用实验和计算工具，通过特别关注对大型风力涡轮机阵列具有重要意义的大尺度湍流和动能垂直通量，预测和改善风电场性能。 近年来，假定在涡轮机前面有给定的入流，已经投入了大量的努力来提高单个风力涡轮机的效率。此外，了解尾流如何影响下游涡轮机的性能以及对多个这种尾流的叠加进行建模已经受到了相当大的关注;然而，对于大型风力涡轮机阵列如何在风力涡轮机阵列边界层（WTABL）中以较大尺度与湍流大气边界层相互作用的基本了解相对较少。最近的研究表明，大型风电场的一个重要性能限制因素是动能从风力涡轮机上方的高空气流夹带到阵列中的速率。无论单个风力涡轮机的效率如何，或者它与上游风力涡轮机的适应能力如何，最终进入整个阵列的动能的垂直通量在很大程度上决定了可以从大气中提取多少功率流。 本研究的目的是为了更好地了解不同尺度湍流对垂直卷吸过程的限制因素和影响。 由此产生的模型应指导风力涡轮机的位置策略和可能的流量修改，使垂直夹带率可以增加。具体而言，风洞实验加上大涡模拟（LES）将被用来解决以下研究问题：（a）什么是发展和充分发展的WTABL之间的本质区别？(b)流向大尺度相干涡对动能垂直卷吸的相对贡献是什么？(c)阵列中不同风力涡轮机之间的轮毂高度速度和功率输出的时空相关性是什么？(d)是否有特别安排的风力涡轮机阵列，增加，平均而言，夹带？和（e）通过修改转子以增加这种卷吸，是否会影响大规模的流动结构？解决这些问题需要在高度受控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。这些数据将通过与来自大型风电场的相关新现场数据进行比较来补充。 更广泛的影响：风能的强劲增长意味着美国和世界陆地和近岸表面不可忽视的部分可能最终用于大型风力发电场。预测和更好地理解物理过程耦合的改性表面和大气在这样的条件下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，提供必要的工具和见解，以帮助实现美国到2030年风能占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。国际经验（瑞士、西班牙）和工业经验（通用电气）也将在本项目中得到强调。招聘和推广将利用这两个PI？通过在波多黎各的联系（NSF-AGEP和LSAMP）以及JHU的IGERT对复杂系统建模，正在努力招募美国西班牙裔研究生。RPI关于能源和环境的GK-12将利用NSF的资源对教师进行风能问题的培训。私家侦探？的正在进行的推广到巴尔的摩高中将继续，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.