Numerical Investigation of Aeroacoustic Response of an Oscillating-Wing Power ExtractorOA

Oscillating-wing power extractors(OWPEs)are an alternative to rotary wind turbines for smalland medium-scale renewable energy applications.However,the aeroacoustic response of such systems remains largely unexplored.In this study,the power extraction performance and near-field aeroacoustic characteristics of an OWPE are numerically investigated using transient computational fluid dynamics(CFD)simulations coupled with the Ffowcs Williams-Hawkings(FW-H)acoustic model at a Reynolds number Re of 8.58×10^(4).Two important operating parameters,namely the pitching amplitude θ_(o) and reduced frequency f^(*),are varied systematically,and the corresponding near-field sound pressure level(SPL)is measured at 20 receiver locations surrounding the OWPE.The results show that the reduced frequency f^(*)has a strong influence on the near-field overall sound pressure level(OSPL),whereas the effect of pitching amplitude is comparatively less significant.Increasing the reduced frequency broadens the acoustic spectrum and increases the predicted near-field acoustic levels,while the acoustic response remains dominated by low-frequency components.Flow-field analysis reveals that the formation,growth,and shedding of the leading-edge vortex(LEV)strongly influence both the power extraction performance and the near-field aeroacoustic characteristics.The Technique for Order Preference by Similarity to Ideal Solution(TOPSIS)-based multi-criteria analysis identified θ_(o)=80◦and f^(*)=0.16 as the optimal operating condition,providing the best compromise between power extraction and near-field acoustic levels.