Experimental study on interaction of the counter-rotating rotors in a wind turbine

A experimental study was conducted to examine the feasibility and aerodynamic performance of a counter-rotating rotor system for a small horizontal axis wind turbine (CRWT) in a wind tunnel, and the study aim is to test the effect of the upstream rotor on the downstream rotor for power extraction. Initial experimental results indicated greater power extraction and performance from the counter-rotating configurations than that of the single rotor design. The rotation of upstream rotor has important influence on the power output of the downstream rotor, however, the rotation of downstream rotor has almost no effect on the power output of the upstream rotor.