强非线性波作用下海上风机动力特性模型试验研究

Experimental Research on the Dynamic Characteristics of Offshore Wind Turbine Model Under the Action of Highly Nonlinear Waves

[目的]单桩式基础是目前近海海上风电场应用最广泛的支撑结构。中国海洋环境多为浅水和中等水深,受到非线性波浪影响较为明显。与行进波相比,聚焦波可以在短时间内形成一个作用在桩柱上、比常规波浪力大的冲击力,从而影响海上风机的运行性能和疲劳寿命。文章旨在探究强非线性波浪作用下海上风机单桩基础荷载特性,掌握聚焦波与基础相互作用规律,为工程设计提供参考。[方法]文章采用水池模型试验的方法对NREL 5 MW单桩海上风机开展研究,缩尺比例为1:80。结合我国东部沿海风电场的海洋环境条件,选取了三种典型聚焦波模型,通过浪高仪器和测力天平分别记录了不同工况下单桩周围波浪爬高和底部受力变化情况。[结果]结果表明:桩基所受的水平波浪力具有很强的瞬态性;单桩基础所受水平波浪力在聚焦波的作用下会突然增大,在波谷会受到反向冲击力。[结论]文章揭示了聚焦波引起的海上风机单桩基础荷载变化规律,证实了非线性波浪对于风机基础动力特性的重要影响,相关成果具有较高的理论和工程应用价值。

[Introduction]Monopile foundation is currently the most widely used support structure for offshore wind farms.For offshore wind farms in the medium water depth area such as Dafeng,Binhai and Sheyang in China,the design waves are very close to the wave breaking limit.Compared with the traveling wave,the focused waves can form an impact force on the pile column in a short time,which is larger than the conventional wave force,and undermines the operational performance and fatigue life of the offshore wind turbines.[Method]In this paper,NREL 5 MW monopile wind turbine model tests were carried out to investigate the hydrodynamic response of large offshore wind turbines to highly nonlinear waves and other harsh waves in combination with the marine environmental conditions of China's eastern coastal wind farms,focusing on exploring the test techniques for monopile wind turbines,and the mechanism of interaction between focused waves and monopiles under the action of focused waves.[Result]The results show that,the horizontal wave force on the pile foundation,which is significantly transient,will suddenly increase when the focused waves act on the monopile foundation,and receive the reverse impact force at the trough of focused wave fluctuation.[Conclusion]The results are of high theoretical value and have engineering prospect for the safe operation of monopile foundation.