CIRCULATION CONTROL FOR THE ROTORS OF LARGE HORIZONTAL AXIS WIND TURBINES

Abstract

Circulation control, augmenting aerofoil lift and reducing drag using air jets is long established but little considered for wind turbine applications. This is a top-level exploration of the basic concept which involves a substantial part of the rotor blade having low solidity, elliptical sections which generate little lift and drag when passive, greatly moderating extreme storm loads when the rotor is idling. The CC rotor can then be expanded in diameter by ~ 30% within the same loading envelop of a standard rotor with gain in energy capture to compensate for added cost in the rotor systems.