Abstract
The authors had invented a unique wind power unit composed of a large-sized front wind rotor, a small-sized rear wind rotor and a peculiar generator with inner and outer rotational armatures without the traditional stator. In the previous report, the relationship between the acoustic noise and flow conditions around the tandem wind rotor are discussed. Continuously, this paper discusses the effects of the blade profiles on the acoustic noise from tandem wind rotors. The chord of the rear blade should be decreases to reduce the acoustic noise in the tandem propellers.
