The impact of the aerodynamic model fidelity on the aeroelastic response of a multi-megawatt wind turbine

Currently, the wind turbine size is increasing dramatically, and the blades are experiencing large deformations. Accordingly, the aerodynamic force distributions over the blades are changed, and hence aeroelastic analysis has become of great importance. The state-of-the-art simulation tools for wind turbines aeroelasticity utilize engineering models to find the aeroelastic response. These tools use simplified methods such as BEM to find the unsteady aerodynamic loads and 1D structural models to determine the deformations. They are computationally cheap, but they are based on different corrections to account for the unsteadiness and the 3D effects. These corrections might lead to a decrease in model accuracy. Therefore, the objective of the present studies is to compare the results of engineering models to CFD-based aeroelastic simulations that do require less empirical modeling. The Multi-Body Simulation (MBS) solver SIMPACK is used to determine the dynamic response of the rotor and the blade aerodynamic loads were calculated by an integrated third-party module (AeroDyn) based on BEM. The block-structured CFD solver FLOWer is utilized to obtain the aerodynamic blade loads based on the time-accurate solution of the unsteady Reynolds-averaged Navier-Stokes equations. The engineering model predicted smaller power and thrust compared to the values obtained using the high-fidelity CFD-based aeroelastic model. Moreover, 1%–1.5% increase in the power and thrust was predicted from the engineering model by increasing the number of polars used along the blade.