Collaborative Research: Wind turbine - atmospheric boundary layer interactions: model experiments and implications on numerical simulations

直径在100米左右的水平轴风力涡轮机是有史以来最大的旋转机器。与大多数炼油厂不同，它们的正常运行条件受到自然变化的强烈影响。当在风力发电场中作为大型阵列部署时，风力涡轮机在它们之间以及与大气湍流边界层相互作用。为了优化它们的选址和几何布置，以及量化风电场在不同尺度上对陆地-大气交换的总体影响，大气传输过程的计算机建模需要尽可能真实地对风力涡轮机进行参数化。智力优势：拟议的研究是一个风洞实验研究的流动和能量在风力涡轮机阵列，多尺度分析的数据动机，专门解决计算机建模和参数化问题。关于风力涡轮机叶片空气动力学已经知道很多，但是关于风力涡轮机与湍流、高度可变的环境的相互作用的建模知识还远没有发展。拟议的研究将使用新一代流体动力学仪器来解决这一差距，与以前的工作相比，分辨率大大提高，再加上新的数据分析技术。立体粒子图像测速法将用于测量中性层结下的风力涡轮机阵列风洞模型中的高分辨率速度图。（i）模型参数（如阻力系数或功率系数、有效粗糙度高度等），包括它们对流动特性和阵列几何形状的依赖性。(ii)相干周期结构在螺旋尾流中的作用，特别强调它们对应力的影响。借用为多阶段应力测试开发的概念，数据将用于测量"确定性应力"。这些压力的相对重要性将被量化，并提出可能的模型。(iii)将通过相似性方法检查平均速度和应力分布的标度行为。(iv)跨尺度的能量通量将进行检查，使用大涡模拟和次网格尺度建模的背景下新开发的分析工具。结果将被浓缩成有用的参数化和模型，可用于微型，中型和全球规模的模拟风力涡轮机阵列在大气中。更广泛的影响：拟议的研究将有助于提高从大气环境中提取风能的适用性，效率和长期可持续性的理解。在更广泛的知识影响方面，拟议中的大型人造机械，相干流结构和随机湍流背景之间的相互作用的研究可能会导致新的“空间尺度时间”建模概念和分析工具。在推广方面，将与现有的NSF资助的研究生教育和教授联盟（AGEP）计划协同发展。目前参与中央纽约-波多黎各（CNY-PR）研究生教育联盟和RPI教授会的重点是招募和指导少数民族学生从事学术事业。计划在波多黎各的卡瓜斯再设立一个中心--"能源和可持续发展国际中心"。拟议的研究将使JHU，RPI，这个计划中的中心，和AGEP合作伙伴Turabo大学和波多黎各-Mayaguez大学之间产生有益的协同作用。还计划招聘波多黎各的本科生在该项目的暑期实习期间工作，并指导博士后学者从事能源和可持续性领域的学术事业。

With diameters on the order of 100 meters, horizontal axis wind-turbines are the largest rotating machines ever built. Unlike most turbomachines, their normal operating conditions are strongly influenced by natural variability. When deployed as large arrays in wind farms, wind turbines interact among themselves and with the atmospheric turbulent boundary layer. To optimize their siting and geometric arrangements, as well as to quantify the aggregate effects of wind-farms on the land-atmosphere exchanges at various scales, computer modeling of the atmospheric transport processes requires parameterizing the wind turbines as realistically as possible. Intellectual Merit: The proposed research is a wind-tunnel experimental study of flow and energetics in wind-turbine arrays, and multi-scale analysis of data motivated specifically to address computer modeling and parameterization issues. Much is already known about wind-turbine blade aerodynamics, but the knowledge on modeling the interactions of wind-turbines with the turbulent, highly variable environment is far less developed. The proposed research will address this gap using new-generation fluid dynamics instrumentation at a much increased resolution compared to prior work, coupled with new data analysis techniques. Stereo Particle-Image-Velocimetry will be used to measure high-resolution velocity maps in wind-tunnel models of wind-turbine arrays under neutral stratification. The data will be used address the following issues: (i) Model parameters (such as drag or power coefficients, effective roughness height, etc..), including their dependence on properties of the flow and array geometry. (ii) The role of coherent periodic structures in helical wakes, with specific emphasis on their impact on stresses. Borrowing from concepts developed for multi-stage turbomachinery, the data will be used to measure the "deterministic stresses". The relative importance of such stresses will be quantified and possible models proposed. (iii) The scaling behavior of mean velocity and stress profiles will be examined via a similarity approach. (iv) Energy fluxes across scales will be examined, using analysis tools newly developed in the context of Large Eddy Simulation and subgrid-scale modeling. Results will be condensed into useful parameterizations and models that may be used in micro, meso, and global scale simulations of wind-turbine arrays in the atmosphere. Broader impacts: The proposed research will contribute to advance the applicability, efficiency, and understanding of the long-term sustainability of wind energy extraction from the atmospheric environment. In terms of intellectual broader impacts, the proposed research on the interactions among large human-made machinery, coherent flow structures, and a random turbulent background may lead to new 'space-scale-time' modeling concepts and analysis tools. In terms of outreach, synergies with an existing NSF-funded Alliance for Graduate Education and Professoriate (AGEP) program will be developed. Current involvement in the Central New York-Puerto Rico (CNY-PR) Alliance for Graduate Education and the Professoriate at RPI focuses on recruiting and mentoring minority students for academic careers. An additional center is planned for Caguas, Puerto Rico - "The International Center on Energy and Sustainability". The proposed research will enable useful synergies between JHU, RPI, this planned Center, and AGEP partners University of Turabo and University of Puerto Rico-Mayaguez. Recruitment of undergraduate students from Puerto Rico to work during summer internships on this project is also planned, as well as mentorship of postdoctoral scholars for academic careers in the field of energy and sustainability.