Space-time Loadings on Wind Turbine Blades driven by Atmospheric Boundary Layer Turbulence: Coupling LES and DES

0933647 BrasseurProject概述风力涡轮机的停机时间一直高于预期，这是因为缺乏对转子和脉动风场之间的相互作用所产生的沿转子叶片跨度的真实时空载荷的定量知识。大气近地面层(ASL)含有强烈的非均匀相干湍流结构，产生相对于快速旋转的叶片的高时空风矢量方向和大小的变化，从而产生非定常的空间相关载荷。叶片的振动、弯曲和扭曲、与跨度相关的非定常边界层分离和动态失速、噪声、尾涡的形成以及叶片的螺距控制都是由转子叶片上的非定常力和力矩引起的。这些载荷综合在一起，在传动轴上产生波动的力，并传递到变速箱，这是故障的热点。虽然现场数据不能提供所需的全时空风数据，但模拟一直受到分辨率、精度和缺乏真实时空大气风输入的限制。智能优点：该项目将开发一种复杂的计算能力，在时空中得到很好的分辨，准确地预测旋翼空气动力学和载荷的细节，以响应大范围大气状态下的真实ASL湍流结构。该计算设施将用于分析风力涡轮机负载和轴上脉动力的详细动力学，并将成为验证低阶设计模型、控制系统设计和测试以及研究噪声、顺风相互作用、变速箱设计等重要相关问题的计算试验台设施的基础。该设施将通过耦合两类模拟和代码在NSF Tera网格的大规模并行框架内开发：(1)广泛大气状态下的大气边界层(ABL)的伪谱大涡模拟(LES)，以及(2)采用“分离涡模拟”(DES)策略对单个旋翼叶片进行贴体气动模拟。更广泛的影响：该研究计划通过提供可开发和验证低阶设计工具的高级资源，可能对风力涡轮机设计产生广泛影响。它将启动一项长期努力，我们计划将其扩大到包括广泛的风力涡轮机设计问题。PIS将为宾夕法尼亚州立大学能源与环境学院(PSIEE)和可持续发展中心(CFS)的外展工作做出贡献，后者通过绿色能源项目直接与本科生合作。他们将为参与SFS项目和其他方面的本科生开发简短的讲座。重点将是“对与风力发电相关的高水平科学技术研究的需求”。他们还计划与宾夕法尼亚州立大学公共广播服务(WPSU)合作，开发一种针对高中和本科生的基于网络的“数字学习对象”，展示在风能领域进行高水平科学研究的兴奋之处。

0933647BrasseurProject SummaryWind turbine downtime has been consistently higher than anticipated because of a lack of quantitative knowledge of the true space-time loadings along the span of the rotor blades that arise from the interactions between the rotor and the fluctuating wind field. The atmospheric surface layer (ASL) contains strongly inhomogeneous coherent turbulence structure that generates high variability in space-time wind vector orientation and magnitude relative to the rapidly rotating blades, creating non-steady spatially-dependent loadings. The non-steady forces and moments along the rotor blades underlie the vibrations, bending, and twisting of the blades, span-dependent non-steady boundary layer separations and dynamic stall, noise, trailing vortex formation, and blade pitch control. These loadings integrate to produce fluctuating forces on the drive shaft that are transferred to the gearbox, a hot point for failure. While field data cannot provide the needed wind data in full space-time, simulations have been limited by resolution, accuracy, and the lack of true space-time atmospheric wind inputs.Intellectual Merit: This project shall develop a sophisticated computational capability, well resolved in space-time that accurately predicts the details of rotor aerodynamics and loadings in response to true ASL turbulence structure over a wide range of atmospheric states. The computational facility will be applied to analyze the detailed dynamics underlying wind turbine loadings and fluctuating forces on the shaft and will also form the basis of a computational test-bed facility for validation of lower-order design models, for design and testing of control systems, and for studies of important related issues such as noise, downwind interactions, gearbox design, etc. The facility will be developed within the massively parallel framework of the NSF tera-grid by coupling two classes of simulation and code: (1) pseudo-spectral large-eddy simulation (LES) of the atmospheric boundary layer (ABL) over a wide range of atmospheric states, and (2) body-fitted aerodynamic simulations over individual rotor blades using a "detached eddy simulation" (DES) strategy. Broader Impacts: This research program could broadly impact wind turbine design by providing a high level resource within which low-order design tools can be developed and validated. It will initiate a long-term effort that we plan to grow to include a broad range of wind turbine design issues. The PIs shall contribute to the outreach efforts of the Penn State Institutes of Energy and the Environment (PSIEE) and Center for Sustainability (CfS) which works directly with undergraduate students through green energy projects. They will develop short lectures for undergraduate students involved in SfS projects and elsewhere. The focus will be "the need for high-level science and technology research related to wind power." They also plan to work with the Penn State Public Broadcasting Service (WPSU) to develop a web-based "digital learning object" directed at high school and undergraduate that shows the excitement of doing high-level scientific research in wind energy.