A consistent vortex model for the aerodynamic analysis of vertical axis wind turbines

A consistent two dimensional vortex type aerodynamic model for VAWTs is presented alongside with its validation against measured data. The flow solver assumes incompressible and inviscid conditions. It combines a source-vorticity panel formulation for the blades and a vortex blob representation of their wakes. By construction the model accounts for the effects of curvature of the relative to the blade inflow while blade vortex interactions are modelled by locally correcting the position of the wake vortices when they impinge on the blade. In order to get realistic loading estimations, lift and drag are corrected using a modified version of the ONERA model in which only the contribution of the separated generalised circulation is considered. Comparisons against wind tunnel tests on model rotors as well as full scale, field measurements on a 12 kW VAWT indicate that the model predicts well the aerodynamic loads on the blades and the power output of the rotor.