Hysteresis effect on airfoil stall noise and flow field

Y. (杨延年) Yang, C. (李辰昭) Li, S. Pröbsting, X. (刘骁敏) Liu, Y. (刘宇) Liu, E. J. G. Arcondoulis

Research output: Contribution to journalArticle (Academic Journal)peer-review

1 Citation (Scopus)

Abstract

The effect of hysteresis on the lift coefficient of an airfoil is well-known, i.e., the lift coefficient is higher during the upstroke than during the downstroke for the same angle of attack (AoA). In contrast, the effect of hysteresis on the noise emission has not been reported before. In order to investigate this effect, a NACA 0012 airfoil is investigated during upstroke and downstroke between zero and post-stall AoA at a constant Reynolds number of 5.1 × 10 5. A map of the noise emission vs AoA is presented revealing tonal noise emission at low AoA, and broadband noise beyond the linear range of lift coefficient. The trend of overall sound pressure level vs AoA shows two local peaks: one at 4.4° with high tonal noise and a second one at 12.6° where the maximum lift coefficient is observed. Flow measurements near the leading edge and trailing edge by particle image velocimetry show that the airfoil noise trend vs AoA is dominated by the trailing-edge flow features. The magnitude of noise emission during the upstroke is higher than that during the downstroke in the hysteresis loop, although the velocity fluctuation magnitude is smaller. This implies that the vortex coherence during upstroke is higher than downstroke, which is evidenced by a more coherent vortex during the upstroke.
Original languageEnglish
Article number095101
Pages (from-to)095101
Number of pages1
JournalPhysics of Fluids
Volume35
Issue number9
DOIs
Publication statusPublished - 1 Sept 2023

Bibliographical note

Funding Information:
Yannian Yang thanks the Laboratory of Aerodynamic Noise Control, China Aerodynamics Research and Development Center (Grant No. 2201ANCL20220102) and National Natural Science Foundation of China (Grant No. 11802114) for the support. Yu Liu would like to thank the National Natural Science Foundation of China (Grant No. 92052105).

Publisher Copyright:
© 2023 Author(s).

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