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

Abstract

[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.

Keywords

• offshore wind power
• offshore wind turbines
• focused waves
• model tests
• dynamic response analysis