Oscillating-wing Power Generation

Numerical and experimental methods are described for the investigation of an oscillating-wing generator or wingmill. The numerical approach applies a previously developed, unsteady, in-compressible panel method incorporating a non-linear, deforming wake model to compute the unsteady ow about an airfoil undergoing speciied pitch and plunge motions. An experimental model is described which can duplicate much of the parameter-space available to the panel method. Numerical results are presented demonstrating conngurations that yield high eeciencies. Results are compared to the wingmill experiments of McKinney and DeLaurier. NOMENCLATURE A area swept out by the wing, in terms of c 2 C D drag coeecient, drag=(q 1 S) C L lift coeecient, lift=(q 1 S) C M moment coeecient about x p , moment=(q 1 Sc) C P power coeecient, power=(q 1 SV 1) = C L _ y + C M _ C PI ideal power coeecient, P I =(q 1 SV 1) C PT total power coeecient, P T =(q 1 SV 1) c chord length f oscillation frequency in Hz h plunge amplitude, in terms of c k reduced frequency, 2fc=V 1 P I ideal power, 16=27P T P T total power available, q 1 V 1 A q 1 freestream dynamic pressure, 1=2 1 V 2 1 S wing area t time V 1 freestream velocity x p pivot location, in terms of c y plunge displacement, in terms of c angle of attack (AOA) sinusoidal pitch amplitude PD eeciency based on drag, C P =C D PI ideal eeciency, C P =C PI PT total eeciency, C P =C PT 1 freestream density nondimensional time, tV 1 =c INTRODUCTION