Velocity measurement of flow around model vertical axis wind turbines

A study of the air flow around five different model vertical axis wind turbines has been undertaken using Particle Image Velocimetry (PIV) in a closed loop wind tunnel. Turbine models include a 'standard Savonius' design, a 'deep' blade and a 'shallow' blade and two blades with compound blade curvature. Measurements were obtained at six constant phase angles of the turbine rotor. Large scale flow structures are evident in all designs such as vortices shed from blade surfaces. Results show the rotor relies on lift forces. Further analysis shows that there is considerable interaction between flow over the forward blade and the wake of the trailing blade.