洋流冲刷效应作用下海上风力机支撑结构动力学特性与防护方法研究

The mono-pile foundations of offshore wind turbines and the seabed in the neighbouring area suffer serious scouring issues particularly under the coupled wind, wave and tidal current loading conditions. Due to the scours over time, the mechanical properties of the ‘seabed-foundation’ system would be modified gradually and the reliability and safety of the turbine foundation will be lowered eventually. The purpose of this project is just a timely effort in order to address this issue. Following the detailed investigation of the scours and their effects on the wind turbine foundation and neighbouring seabed, an appropriate method will be established first for scour assessment. Then, the influence of scour effects on dynamic characteristics of supporting structure will be studied. Finally, with the aid of the proposed scour assessment method, an innovative scour protection technique based on the flow-guiding mechanism will be developed, optimised and verified. The major contributions of this research include: (1) the scour resultant nonlinear vibration and stability issues of offshore wind turbine foundations are investigated for the first time, which paves the way to the further research on the safety and reliability of offshore wind turbines in harsh offshore environment; (2) a cost-effective and efficient scouring protection technique is successfully developed, which improves the reliability and safety of offshore wind turbines thus significantly lowers the cost of energy of offshore wind power.

海上风力机桩式基础长期承受复杂的风、浪、流等耦合作用，会引起基础周围海床出现冲刷现象。而基础局部冲刷效应在导致结构承载能力降低的同时，还会使支撑结构的振动特性发生改变，对风电结构的动力响应和稳定性造成极为不利的影响，严重威胁到风力机的安全和可靠运行。本项目拟针对洋流冲刷效应作用下海上风力机支撑结构的动力学特性与防护方法进行理论和试验研究。研究复杂海况条件下海上风力机桩式基础洋流冲刷机制与评估方法，分析基础冲刷作用下支撑结构的非线性振动特性，揭示冲刷效应对支撑结构动力学特性及稳定性的影响规律，发展洋流冲刷防护设计方法与技术。为提高我国海上风力机动力学设计技术水平，确保风力机在海上复杂环境下运行的安全与可靠提供理论和技术支持。

海上风力机桩式基础长期承受复杂的风、浪、流等耦合作用，会引起基础周围海床出现冲刷现象。而基础局部冲刷效应在导致结构承载能力降低的同时，还会使支撑结构的振动特性发生改变，对风电结构的动力响应和稳定性造成极为不利的影响，严重威胁到风力机的安全和可靠运行。本项目主要针对洋流冲刷效应作用下海上风力机支撑结构的动力学特性与防护方法进行理论和试验研究。建立了海上风力机桩基的有限元两相流流固耦合模型，分析了单向流条件下单桩基础周围冲刷坑的形成规律；采用P-Y曲线法探讨了冲刷坑对桩基水平承载性的影响，分析了不同冲刷深度对支撑结构动力学特性的影响规律；自主设计建设了用于洋流冲刷等海上风电装备试验研究的海洋环境模拟循环水槽试验平台; 利用吸能与扰流机制，发展了基于洋流发电机和“渔网”等的海上风电基础洋流冲刷防护方法和技术。为提高我国海上风力机动力学设计技术水平，确保风力机在海上复杂环境下运行的安全与可靠提供理论和技术支持。本项目取得的主要研究成果包括：在国内外期刊发表学术论文9篇，其中SCI收录期刊论文8篇；授权国家发明专利授权5项，国际（日本）发明专利1项；获中国发明协会创业创新一等奖1项；培养硕士研究生6人，已获学位4人。