Experiments on an oscillating aerofoil and applications to wind energy converters

Abstract

Forces measured on a two-dimensional NAG A 0012 aerofoil oscillating in pitch and combined pitch-heave are presented. Amplitudes of pitch were up to 34 deg and heave up to 0.2 chord. Reynolds numbers ranged from 0.7 x 10 to 3.3 x 10 and reduced frequency wc/2 V up to 0.45. The application of this data to the prediction of Darrieus turbine performance, by approximating blade-wind interaction to a pure pitch oscillation, showed some significant differences from steady aerofoil predictions. The use of an aerofoil oscillating in combined heave-pitch as a wind-energy converter is treated briefly.