The aerodynamic modeling of wind turbine blades using different levels of fidelity*

We study the aerodynamic modeling of wind turbine blades. We will explain the difference between blade-element momentum theory, vorticity-based methods, actuator lines and blade resolved simulations. We show that even on simple simulations of uniform inflow with constant rotational speed, these methods provide different predictions of aerodynamic quantities along the blade. These differences translate to differences in thrust and power prediction of more than 50% in some cases. We focus on the fundamental assumptions behind the different approaches to explain where the differences are coming from. Most differences come from the spanwise distribution of vorticity/forces from blade elements. Tip and root corrections also play an important role and can influence the results significantly.