Wind Turbine Blade Instability
Offshore wind energy has been growing rapidly due to its capacity for utilizing much larger turbines and thus higher power generation compared to onshore. Long wind turbine blades are susceptible to experiencing aeroelastic instabilities. We study coupled-mode flutter of rotating and non-rotating flexible wind turbine blades. The dynamic behavior of blades is investigated through theoretical modelling and wind tunnel experimentations. A parametric study is conducted on three different MW-sized wind turbine blades in order to investigate the influence of some of the major systems parameters (weight, flexibility ratio, ...) on the critical flutter speed. The presence of stochastic parameters in systems experiencing flow-induced instabilities can influence the onset of dynamic instability and thus a deterministic analysis of wind turbine blade dynamics is not sufficient. The influence of uncertainty in various system parameters on the onset of coupled-mode flutter is also studied initially using Monte-Carlo simulations and then using four different reliability methods.