Influence mechanism and numerical reconstruction method of complex wind field acting on a large-MW floating wind turbine

Abstract

The large-scale wind fields show a series of complex characteristics, including wind shear, turbulence intensity, and spatial coherence, which could significantly affect the coupled dynamic responses of floating wind turbines (FWTs). During numerical simulation, to obtain the coupled dynamic responses of large-scale FWTs more accurately, it is necessary to provide a more accurate simulation of the time scale and spatial scale characteristics of actual measured large-scale wind fields. This study investigated the influence mechanism and numerical reconstruction method of a complex wind field acting on a large-MW floating wind turbine. The influence mechanisms were concluded as follows: Wind shear was found to decrease the mean power generation and increase responses at 1P and 3P frequencies. Turbulent winds could significantly decrease the mean response and increase the low-frequency and 3P responses. The difference in spatial coherent structures between different wind fields was clarified by analyzing the proper orthogonal decomposition mode. As spatial coherence strengthened, the mean responses became smaller, the low-frequency responses became larger, and the 1P and 3P responses became smaller. On this basis, a numerical reconstruction method was proposed in this study to reconstruct large-scale numerical wind fields using wind speeds measured at finite spatial points in model tests or offshore measurements. This method accurately simulates the wind profile characteristics, turbulence intensity distribution along the vertical direction, and spatial coherence parameters of the wind field.