A Hybrid Aerodynamic and Aeroacoustic Modeling for Small Wind Turbines

Abstract

Stall control and pitch control are the most commonly used methods of regulating power. However, through the opportunities presented by the flexible (or teetered) hub of a two-bladed teetered rotor one can also utilize yaw control to regulate power. This is achieved by adjusting the capture area of the rotor disk relative to the prevailing wind direction. This paper presents the aerodynamic and aeroacoustic results obtained from theoretical models for such a rotor when is yawed to the undisturbed flow. The non-axial flow operating conditions results in a variation in the power output and noise spectrum. Some comparisons between calculated and measured noise spectra of a yaw controlled wind turbine show good agreement over all angles up to 60 degrees of yaw.