Fixed Wake Theory for Vertical Axis Wind Turbines

Abstract

A theory for vertical axis wind turbines has been developed using a fixed wake approach. The theory combines some of the best features of vortex and streamtube approaches. This approach accounts for flow differences between fore-and-aft-blade positions that are predicted by vortex methods while retaining the low computation costs associated with streamtube theories. The theory is applied to high tip speed ratio operation of a Darrieus Rotor where the use of linear aerodynamics results in explicit calculation of the induced velocities. Comparison to test results shows good agreement.