Investigations on Effects of Inflow Turbulence on Vortex-Induced Vibrations of a Wind Turbine Airfoil With the Wake Oscillator Model

Abstract

Abstract Design load and vibration for parked conditions are of utmost importance for large-scale modern wind turbines with increasing flexibility, especially edgewise vibration when the blade is at a high angle of attack. In this study, effects of inflow turbulence on vortex-induced vibration (VIV) of a wind turbine airfoil at 90 degrees of attack angle is examined. The study is carried out using the wake oscillator model, which is identified from the fluid-structure interaction (FSI) simulations. The turbulence induced dynamics is observed to be significantly distinct from that under uniform inflow and is heavily dependent on the turbulence intensity and mean velocity. The vibration response under inflow turbulence represents intermittency and broadband frequency characteristics near natural frequency and vortex shedding frequency since the inflow fluctuation drives the system to alternately enter and exit the frequency lock-in regime. In addition, Gaussian process regression is used to obtain a surrogate from input inflow conditions to output VIV loads. The results show that the incoming turbulence increases the risk of high amplitude vibration in the original low amplitude velocity regime, especially for high turbulence intensities. The conclusions may provide a new perspective for VIV response evaluation of the wind turbine under inflow turbulence.