Load prediction for large-scaled HAWT based on a nonlinear structural-aerodynamic coupled method

Load prediction is becoming difficult due to the larger, lighter and more flexible blades of large-scaled horizontal axis wind turbine (HAWT), which leads to the nonlinear aero-elastic responses. Based on geometrically exact beam (GEB) theory for blade structural dynamics, a free-vortex wake (FVW) model for the prediction of unsteady aerodynamic loads and a partitioned loosely coupled methodology to exchange the data at the interface, a nonlinear FSI model has been developed in this study. Through comparison of NREL UAE Phase VI experimental data and the load predicted by the nonlinear model, the capability to accurately predict the aerodynamic loads is validated. The nonlinear beam model is also validated by several cases which all show a good agreement with results obtained by other authors. Finally, dynamic responses for NREL 5 MW RWT are estimated and compared with results from linear model. The results show that the coupled method is capable of evaluating blade nonlinear responses for large-scaled HAWT.