Experimental investigation on the flow field and performances of a Savonius-Darrieus wind turbine

In this paper, measurements performed on a vertical axis wind turbine (VAWT) model are reported. The turbine is a combination of Savonius and Darrieus rotors to optimize performances in medium-low wind regimes. To this end, the turbine is positioned into a wind-tunnel to derive instantaneous and averaged velocity fields by means of Particle Image Velocimetry (PIV). PIV data allow to derive specific fluid flow phenomena on each single and on combined geometrical configurations. These results are also compared with electrical measurements to determine performances, efficiency and the best working conditions