Wave-Structure Interaction of Floating Wind Turbines - A Combined Numerical and Experimental Investigation

浮动式风力涡轮机是一种新型的可再生能源设备，设计用于深水（60米）运行，大部分海上风能资源都在深水中发现。这些浮式涡轮机在结构上不同于其他现有的海上系统，其在海上条件下的结构稳定性尚未得到广泛的测试。这项跨学科的研究工作将利用地震工程的实验设施和最先进的计算方法来研究浮动风力涡轮机在海浪中的动态结构响应。本文将建立两个模型，一个频域模型和一个非线性时域模型来研究流固耦合问题。对于波体相互作用的模拟，第一个模型采用线性边界元模型，而第二个模型采用全非线性混合欧拉-拉格拉格方法。两种模型均包括系泊系统的全面、全非线性动力学模型和结构响应的有限元模型。双模型方法可以研究系统的长期响应（例如疲劳研究）和由于大波（例如异常波）引起的瞬态响应。研究计划将集中在三个方面：波场中的长期结构响应、波-结构共振和对大波的响应。对于模型验证研究，将在一个65kw的系统上进行全尺寸振动台实验，并将记录的结构响应与模型预测进行比较。这些模型将被用来预测一个5兆瓦系统的性能。这项研究具有潜在的变革性，因为它将为评估当前浮动风力涡轮机设计的可行性提供新的工具。这项研究也可以用来指导未来深水海上风力发电场的发展。这项工作的一个独特之处在于它使用了地震工程工具，特别是加州大学圣地亚哥分校的大型高性能室外振动台，来研究海上风能结构。除了对直接参与研究工作的本科生和研究生进行培训外，基于他们研究的学习材料将被纳入现有的本科生和研究生结构和流体力学课程。其他活动包括使用加州大学圣地亚哥分校的大型高性能户外振动台作为示范，向来自代表性不足群体的K-12学生展示与可再生能源相关的主题。该设施的网站将更新，包括浮动风力涡轮机。

0967023ZhuFloating wind turbines are novel renewable energy devices designed to operate in deep waters (60 m), where most of the offshore wind energy resource is found. These floating turbines are structurally different from other existing offshore systems, and their structural stability in offshore conditions has not been extensively tested. Intellectual Merit This interdisciplinary research effort will make use of an experimental facility for earthquake engineering and state-of-the-art computational methods to study the dynamic structural responses of floating wind turbines in ocean waves. Two models, a frequency-domain model and a nonlinear time-domain model, will be developed to study the fluid-structure interaction problem. For simulations of wave-body interaction, the first model uses a linear boundary element model, while the second model applies a fully-nonlinear mixed-Eularian-Lagragian method. Both models include a comprehensive, fully-nonlinear dynamic model of the mooring system and a FEM model of the structural responses. The two-model approach enables the study of both long-term responses of the system (e.g. for fatigue studies) and transient response due to large waves (e.g. rogue waves). The research plan will focus on three areas: long-term structural response in wave fields, wave-structure resonances, and responses to large waves. For the model verification studies, full-scale shake table experiments will be carried out on a 65 kW system, and the recorded structural responses will be compared with model predictions. The models will then be used to predict the performance of a scaled-up 5 MW system. This research is potentially transformative because it will provide new tools to evaluate the feasibility of current designs for floating wind turbines. This research could also be used to guide the development of future deep-water offshore wind farms.Broader Impacts A unique aspect of this work is that it uses earthquake engineering tools, specifically the Large High-Performance Outdoor Shake Table at University of California - San Diego, to study offshore wind energy structures.In addition to training of undergraduate and graduate students directly involved in the research effort, learning materials based on their research will be incorporated into existing undergraduate and graduate structural and fluids mechanics courses. Other activities include using the Large High-Performance Outdoor Shake Table at University of California at San Diego as a demonstration to reach out to K-12 students from under-represented groups on topics related to renewable energy. Websites for this facility will be updated to include the floating wind turbine.