Interactions of a Wind Turbine Array with a Thermally Stratified Atmospheric Boundary Layer: Flow Structures, Energy Fluxes and Modal Behavior

1034581 CalIntellectual Merit风力涡轮机阵列在高度可变的自然条件下运行，如高度湍流变化、表面地形和温度梯度。 特别是，大气的热分层产生热通量的垂直交换，这对气流的动能有直接影响。 风力涡轮机（WT）阵列对这些交换和分层大气的影响是未知的。 洞察这种相互作用可以延长WT的寿命，最大限度地提高功率提取出WT阵列，并帮助了解这种阵列对大气的影响。拟议的研究重点是在风洞中的气流，通量和能量学的风涡轮机阵列的实验研究。 本研究的目的是量化和了解大气交换和功率提取的分层大气湍流边界层（ATBL）耦合的风力涡轮机阵列。 目前，研究分层是为了了解污染物的扩散，而风力涡轮机的研究主要集中在叶片的空气动力学和从单个WT脱落的尾流。 拟议的研究将检查的行为下的热分层的风力涡轮机阵列。 这些实验研究将在波特兰州立大学（PSU）绿色建筑研究实验室的最先进的风洞设施中进行。层析成像粒子图像测速仪和冷线风速仪将分别用于测量实验WT阵列中的高分辨率速度和温度图。 结果将被浓缩成有用的参数化和模型，可用于微型，中型和全球模拟风力涡轮机阵列在一个稳定和不稳定的分层大气。拟议的研究旨在推进理解风能提取从大气环境下的热分层，最终促进WT阵列在现实条件下的设计。更广泛的影响教育计划强调跨文化和国际研究经验的本科生和研究生。 将从图拉博大学（波多黎各）和PSU招募三名本科生参加研究密集型暑期项目。 这些学生将通过使用最先进的风洞测试和流动可视化设施来接触风能的工程方面。 研究生将在夏季前往挪威，与挪威国防研究机构（FFI）的研究人员就研究的建模方面进行合作。外展计划强调让高中生接触STEM主题。 风洞设施能够使用基于网络的平台远程进行实验。 远程风洞实验将与Gladstone高中合作在高中教室进行，让学生接触STEM和可持续发展主题。 通过以学校为基础的方案，俄勒冈州梅萨工程科学成就项目努力增加俄勒冈州少数民族和妇女工程师的人数。 PI和研究生将参加梅萨日，通过梅萨计划招募的学生进行流体力学动手实验，并辅以对PSU风洞设施的图尔斯参观。

1034581CalIntellectual Merit Wind turbine arrays operate under highly variable natural conditions such as high turbulence variability, surface terrain and temperature gradients. In particular, thermal stratification of the atmosphere produces vertical exchanges of heat flux, which have direct impact on the kinetic energy of the flow. The influence of wind turbine (WT) arrays on these exchanges and the stratified atmosphere is not known. Insight on such interactions can prolong the life of the WTs, maximize power extraction out of the WT arrays, and help understand the impact of such arrays on the atmosphere.The proposed research focuses on an experimental study of flow, fluxes and energetics of wind turbine arrays in a wind tunnel. The goal of this study is to quantify and understand the atmospheric exchanges and power extraction on a stratified atmospheric turbulent boundary layer (ATBL) coupled with a wind turbine array. Currently, stratification is studied to understand pollutant dispersion, whereas wind turbine studies focus mainly on the aerodynamic of blades and wakes shed from a single WT. The proposed research will examine the behavior of wind turbine arrays under thermal stratification. These experimental studies will be carried at the state-of-the-art wind tunnel facility housed in the Green Building Research Laboratory at Portland State University (PSU).Tomographic particle image velocimetry and cold-wire anemometry will be used to measure high-resolution velocity and temperature maps, respectively, in the experimental WT array. Results will be condensed into useful parameterizations and models that may be used in micro, meso, and global simulations of wind-turbine arrays in a stably and unstably stratified atmosphere. The proposed research seeks to advance understanding of wind energy extraction from the atmospheric environment under thermal stratification to ultimately facilitate the design of WT arrays under realistic conditions.Broader ImpactsThe education plan emphasizes cross-cultural and international research experiences for both undergraduate and graduate students. Three undergraduate students will be recruited from Turabo University (Puerto Rico) and PSU to participate in a research-intensive summer program. These students will gain exposure to engineering aspects of wind energy by working with state-of-the-art facilities for wind tunnel testing and flow visualization. Graduate students will travel to Norway to during the summer to collaborate with researchers at Norwegian Defense Research Establishment (FFI) on the modeling aspects of the research.The outreach plan emphasizes exposure of high-school students to STEM topics. The wind tunnel facility has the capability to carry out experiments remotely using a web-based platform. Remote wind tunnel experiments will be carried out in a high school classroom in partnership with Gladstone High School to expose students to STEM and sustainability topics. Through school-based programs, Oregon MESA (Mathematics Engineering Science Achievement) strives to increase the number of minority and women engineers in Oregon. The PI and graduate students will participate in MESA Day through hands-on experiments in fluid mechanics with students recruited through the MESA program, complemented by tours to the PSU wind tunnel facility.