Aerodynamic models widely used for Vertical Axis Wind Turbine design (Double Multiple Streamtube and Vortex models) are compared with more time consuming Computational Fluid Dynamics (CFD) simulations as well as with existing experimental data. Comparisons are made for the performance of the Sandia National Laboratories 17m Darrieus turbine, particularly its power, instantaneous torque and (only for the aerodynamic models and CFD) thrust force. The aim of the study is to assess the validity of each method. It is shown that the Double Multiple Streamtube model tends to overestimate torque amplitude and averaged power while RANS CFD gives fairly good predictions at all tip speed ratios tested. It is also shown that the vortex model provides intermediate results between the Double Multiple Streamtube model and CFD simulations.
