Wind turbine aerodynamics: analysis and design

In this paper, the classical work on wind turbine is reviewed, starting from the ground work of Rankine and Froude, then revisiting the minimum energy condition of Betz, and applying modern computing techniques to build codes, based on the vortex model of Goldstein that are both fast and reliable. Such numerical simulations can be used to help analyse and design modern wind turbines in regimes where the flow is attached. Much of the work has been developed under the impulsion of General Electric whose support is gratefully acknowledged. The vortex model has reached a mature state which includes capabilities to model unsteady flows due to yaw, tower interference and earth boundary layer as well as flows past rotors with advanced blade tips that have sweep and/or winglets. When separation occurs on the blades, a higher fidelity model is presented, called the hybrid method, which consists in coupling a Navier-Stokes solver with the vortex model, the Navier-Stokes code solving the near blade flow whereas the vortex model convects the circulation to the far field without dissipation and allows for accurate representation of the induced velocities. Further development of the vortex model includes its coupling with a blade structural model to perform aeroelasticity studies.