Print Email Facebook Twitter Acoustic measurements of a DU96-W-180 airfoil with flow-misaligned serrations at a high Reynolds number in a closed-section wind tunnel Title Acoustic measurements of a DU96-W-180 airfoil with flow-misaligned serrations at a high Reynolds number in a closed-section wind tunnel Author Merino Martinez, R. (TU Delft Aircraft Noise and Climate Effects) van der Velden, W.C.P. (TU Delft Aerodynamics) Avallone, F. (TU Delft Wind Energy) Ragni, D. (TU Delft Wind Energy) Date 2017 Abstract Trailing-edge serrations are passive noise reduction add-ons widely used in wind-turbine applications. This study presents acoustic beamforming results of microphone array measurements of a cambered airfoil (DU96-W-180) in a closed-section wind-tunnel at a Reynolds number of industrial interest. Two different serration geometries with different lengths were tested and compared with the straight-edge baseline airfoil. The serrations were set at a flap angle of 6 degrees. Several flow velocities and angles of attack were tested at three chord-based Reynolds numbers ranging from 5105 to 1.5106. A phased microphone array was used to obtain source maps of the trailing-edge noise; Particle Image Velocimetry (PIV) was employed to obtain information about the turbulent boundary layer approaching the trailing edge; further, a numerical simulation using the Lattice Boltzmann Method (LBM) was performed for comparison. Far-field noise from the experimental data and computations shows a satisfactory agreement. Noise reductions of several dB were obtained, especially at lower frequencies. An increase in high-frequency noise is observed after a crossover frequency, which is assumed to be due to the set flap angle. To reference this document use: http://resolver.tudelft.nl/uuid:25ddc79f-6147-4d92-90cb-23dd342f08b2 Source 7th International Conference on Wind Turbine Noise: Rotterdam – 2nd to 5th May 2017 Event 7th International Conference on Wind Turbine Noise, 2017-05-02 → 2017-05-05, Willem Burger Complex, Rotterdam, Netherlands Part of collection Institutional Repository Document type conference paper Rights © 2017 R. Merino Martinez, W.C.P. van der Velden, F. Avallone, D. Ragni Files PDF DU96_W_180_Final_version.pdf 1.68 MB Close viewer /islandora/object/uuid:25ddc79f-6147-4d92-90cb-23dd342f08b2/datastream/OBJ/view