DOI: https://doi.org/10.61435/ijred.2026.62430
View PDF Download fulltext

Study on the effect of bionic flap based on owl wing contour on aerodynamic noise of airfoil

1College of Energy and Power Engineering, University of Shanghai for Science and Technology, Shanghai, 200093, China

2Marine Design and Research Institute of China, Shanghai,200011, China

Received: 9 Mar 2026; Revised: 17 May 2026; Accepted: 30 Jun 2026; Published: 1 Jul 2026.
Editor(s): H Hadiyanto
Open Access Copyright (c) 2026 The Author(s). Published by Centre of Biomass and Renewable Energy (CBIORE)
Creative Commons License This work is licensed under a Creative Commons Attribution-ShareAlike 4.0 International License.

Citation Format:
Abstract

Modifying flap geometry to reduce trailing-edge turbulence is an effective approach to lower wind-turbine blade aerodynamic noise. Based on the NACA0018 airfoil, a new bionic serrated flap was designed by mimicking the owl wing structure. Numerical methods were employed to investigate its noise reduction mechanism, utilizing Improved Delayed Detached Eddy Simulation (IDDES) and the Ffowcs Williams-Hawkings (FW-H) method. The aerodynamic and aeroacoustic performance of the baseline airfoil, a flat-plate Gurney flap (PGF), a standard serrated flap (SGF), and the bionic flap (BGF) were calculated at different inflow wind speeds (Re = 7×104, 1.4×105 and 2.1×105) under various inflow angles (0°, 6°, 10° and 15°). Numerical results demonstrate that the proposed BGF configuration mitigates the additional noise induced by the traditional Gurney flap, with reductions observed in the overall sound pressure levels across the monitored directivity points. Compared to the baseline airfoil, the BGF demonstrates noise reduction at low angles of attack (AoA < 6°), with a peak OASPL decrease of 4.6 dB. However, this aeroacoustic advantage diminishes rapidly as the AoA exceeds 6°, suggesting that the noise-suppression effectiveness of the bionic contour is highly sensitive to the inflow angle. Analysis of wake vortex structures and turbulence intensity reveals that the curved bionic flap effectively suppresses vortex clusters and turbulence intensity, leading to reduce the airfoil's aerodynamic noise. 

Keywords: Wind turbine; Bionic airfoil; Flow control; Aeroacoustics; Vortex structures
Funding: National Natural Science Foundation of China under contract 52006147;National Natural Science Foundation of China under contract 52476213

Article Metrics:

Article Info
Section: Original Research Article
Language : EN
Recent articles
Hybrid PEMFC–battery systems for marine propulsion: Optimization of efficiency and operational safety CFD analysis of photovoltaic panel performance under variable weather conditions with natural and forced convective cooling Analysis of pine resin potential as an additive on the physical and combustion characteristics of coconut shell bio-briquettes Machine learning in solar energy systems: Methods, applications, and future directions More recent articles
Most cited articles
Production of Solid Fuel by Torrefaction Using Coconut Leaves As Renewable Biomass Woodfuel in Rwanda: Impact on Energy, Poverty, Environment and Policy Instruments analysis A Reliability Based Model for Wind Turbine Selection Microbial Fuel Cells for Simultaneous Electricity Generation and Organic Degradation from Slaughterhouse Wastewater Enhancement of Energy Efficiency and Food Product Quality Using Adsorption Dryer with Zeolite More cited articles
  1. Amini, Y., Emdad, H., & Farid, M. (2015). Adjoint shape optimization of airfoils with attached Gurney flap. Aerospace Science and Technology, 41, 216–228. https://doi.org/10.1016/j.ast.2014.12.023
  2. Amiet, R. K. (1975). Acoustic radiation from an airfoil in a turbulent stream. Journal of Sound and Vibration, 41, 407–420. https://doi.org/10.1016/S0022-460X(75)80105-2
  3. Asada, K., & Kawai, S. (2018). Large-eddy simulation of airfoil flow near stall condition at Reynolds number 2.1×106. Physics of Fluids, 30(8), 085103. https://doi.org/10.1063/1.5037278
  4. Avallone, F., Probsting, S., & Ragni, D. (2016). Three-dimensional flow field over a trailing-edge serration and implications on broadband noise. Physics of Fluids, 28(11), 117101. https://doi.org/10.1063/1.4966633
  5. Brooks, T. F., Pope, D. S., & Marcolini, M. A. (1989). Airfoil self-noise and prediction. NASA Reference Publication, 1218. https://ntrs.nasa.gov/citations/19890016302
  6. Chen, H., Yuan, X., Bi, L., (2020). Simulation of separation flow based on RANS/LES hybrid method. Acta Aeronautica et Astronautica Sinica, 41(8), 183–194. https://doi.org/10.7527/S1000-6893.2020.23642
  7. Chen, K., Feng, W., Zhang, Z. (2024). Study on aerodynamic noise of airfoil with curved serration trailing edge based on characteristics of owl wing. Acta Energiae Solaris Sinica, 45(4), 272–279. https://doi.org/10.19912/j.0254-0096.tynxb.2022-1926
  8. Chen, X., Zheng, L., Cai, G., Qi, X., He, J. (2025). Global perspectives on wind energy innovation: Policy impacts and component-level analysis. Energy, 319, 135000. https://doi.org/10.1016/j.energy.2025.135000
  9. Chong, T. P., Vathylakis, A., Joseph, P. F., Gruber, M. (2013). Self-noise produced by an airfoil with nonflat plate trailing-edge serrations. AIAA Journal, 51(11), 2665–2677. http://dx.doi.org/10.2514/1.J052344
  10. Colonius, T., & Lele, S. K. (2004). Computational aeroacoustics: progress on nonlinear problems of sound generation. Progress in Aerospace Sciences, 40(6), 345–416. https://doi.org/10.1016/j.paerosci.2004.09.001
  11. Feng, W., Chen, K., & Gui, H. (2023). Aerodynamic noise reduction based on bionic blades with non-smooth leading edges and curved serrated trailing edges. Journal of Applied Fluid Mechanics, 16(7), 1402–1413. https://doi.org/10.47176/jafm.16.07.1660
  12. Fujisawa, N., Shibuya, S., Nashimoto,A., Takarno, T (2001). Aerodynamic noise and flow visualization around twodimensional airfoil. Transactions of the Visualization Society of Japan.21(9), 123-129. https://doi.org/10.3154/TVSJ.21.123
  13. Howe, M. S. (1991). Noise produced by a sawtooth trailing edge. The Journal of the Acoustical Society of America, 90(1), 482–487. https://doi.org/10.1121/1.401273
  14. Jacobs, E. N., & Sherman, A. (1937). Airfoil section characteristics as affected by variations of the Reynolds number. NACA Technical Report, 586, 227–267. https://ntrs.nasa.gov/citations/19930091652
  15. Kim, H. J., Lee, S., & Fujisawa, N. (2006). Computation of unsteady flow and aerodynamic noise of NACA0018 airfoil using large-eddy simulation. International Journal of Heat and Fluid Flow, 27(2), 229–242. https://doi.org/10.1016/j.ijheatfluidflow.2005.08.007
  16. Kong, D., Liang, A., Chu, J., (2015) Study on Mechanism of Silent Flight of Owls. Applied Physics, 05(11), 137-146. https://doi.org/10.12677/APP.2015.511019
  17. Li, S., Li, Y., Yang, C., Wang, Q., Zhao, B., Li, D., Zhao, R., Ren, T., Zheng, X., Gao, Z., Xu, W. (2021). Experimental investigation of solidity and other characteristics on dual vertical axis wind turbines in an urban environment. Energy Conversion and Management, 229(1), 113689. https://doi.org/10.1016/j.enconman.2020.113689
  18. Liu, C. (2020). Liutex-third generation of vortex definition and identification methods. Acta Aerodynamica Sinica, 38(3), 413–431. https://doi.org/10.7638/kqdlxxb-2020.0015
  19. Liu, J., Lin, H., & Zhang, J. (2019). Review on the technical perspectives and commercial viability of vertical axis wind turbines. Ocean Engineering, 182(15), 608–626. https://doi.org/10.1016/j.oceaneng.2019.04.086
  20. Liu, T., & Montefort, J., (2007). Thin-airfoil theoretical interpretation for gurney flap lift enhancement. Journal of Aircraft, 44(2), 667–771. https://doi.org/10.2514/1.24423
  21. Liu, X., Tang, H., Wang, X. (2012). Noise-reduction mechanism of bionic coupling blade based on the trailingedge of goshawk wing. Academic Journal of Xi’an Jiaotong University, 46(1), 35–41. https://doi.org/10.7638/kqdlxxb-2017.0162
  22. May, R., Masden, E. A., Bennet, F., Perron, M (2019). Considerations for upscaling individual effects of wind energy development towards population-level impacts on wildlife. Journal of Environmental Management, 230, 84–93. https://doi.org/10.1016/j.jenvman.2018.09.062
  23. Menter, F. R. (1994). Two-equation eddy-viscosity turbulence models for engineering applications. AIAA Journal, 32(8), 1598–1605. https://doi.org/10.2514/3.12149
  24. Meyer, R., Hage, W., & Bechert, D. W. (2006). Drag reduction on Gurney flaps by three-dimensional modifications. Journal of Aircraft, 43(1), 132–140. https://doi.org/10.2514/1.14294
  25. Oerlemans, S., Fisher, M., Maeder, T., Kogler, K. (2009). Reduction of wind turbine noise using optimized airfoils and trailing-edge serrations. AIAA Journal, 47(6), 1470–1481. https://doi.org/10.2514/1.38888
  26. Piorkowski, M. D., Farnsworth, A. J., Fry, M., Rohrbaugh, R.W., Fitzpatrick, J.W., Rosenberg, K.V. (2012). Research priorities for wind energy and migratory wildlife. Journal of Wildlife Management, 76(3), 451–456. https://doi.org/10.1002/jwmg.327
  27. Powell, A. (1964). Theory of vortex sound. The Journal of the Acoustical Society of America, 36(1), 177–195. https://doi.org/10.1121/1.1918931
  28. Si, J., Ai, L., & Qiu, C. (2024). Status and prospect of China’s wind power development in 2023. Water Power, 50(12), 1–4. https://link.cnki.net/urlid/11.1845.TV.20241009.1543.004
  29. Song, D., Yang, Y., Zheng, S., Deng, X., Yang, J., Su, M., Tang, W., Yang, X., Huang, L. (2020). New perspectives on maximum wind energy extraction of variable-speed wind turbines using previewed wind speeds. Energy Conversion and Management, 206, 112496. https://doi.org/10.1016/j.enconman.2020.112496
  30. Sun, X., Zhang, L., Huang, D., Zheng, Z. (2017). New insights into aerodynamic characteristics of oscillating wings and performance as wind power generator. International Journal of Energy Research, 42(2), 776–789. https://doi.org/10.1002/er.3865
  31. Wang, J. J., Li, Y. C., & Choi, K. S. (2008). Gurney flap—lift enhancement, mechanisms and applications. Progress in Aerospace Sciences, 44(1), 22–47. https://doi.org/10.1016/j.paerosci.2007.10.001
  32. Wang, L., & Liu, X. M. (2022). Aeroacoustic investigation of asymmetric oblique trailing-edge serrations enlighted by owl wings. Physics of Fluids, 34(1), 015113. https://doi.org/10.1063/5.0076272
  33. Wilbur, M. L., Mistry, M. P., Lorber, P. F., Blackwell, R., Barbarino, S., Lawrence, T.H., Arnold, T.P. (2018). Rotary wings morphing technologies: State of the art and perspectives. Morphing Wing Technologies, 759–797. https://doi.org/10.1016/B978-0-08-100964-2.00024-1
  34. Wu, X., Hu, W., Huang, Q., Chen, C., Jacobson, M.Z., Chen, Z. (2020). Optimizing the layout of onshore wind farms to minimize noise. Applied Energy, 267(1), 114896. https://doi.org/10.1016/j.apenergy.2020.114896
  35. Yan, Y., Avital, E., William, J., Cui, J. (2020). Performance improvements for a vertical axis wind turbine by means of Gurney flap. Journal of Fluids Engineering, 142(2), 021205. https://doi.org/10.1115/1.4044995
  36. Yang, J., Yang, A., Chen, E., (2017). Numerical research on aerodynamic characteristics and flow fields of airfoil with serrated trailing edge. Journal of Aerospace Power, 32(4), 900–908. https://doi.org/10.13224/j.cnki.jasp.2017.04.015
  37. Yang, Z., Li, X., Zhang, K., (2025) Numerical study on benefits of curved serrations upon suppressing turbulent boundary layer trailing-edge noise. Physics Letters A, 530,130131. https://doi.org/10.1016/j.physleta.2024.130131
  38. Yu, Y., Chen, L., Zheng, Z., (2022). Effect of serrated gurney flap on NACA0018 airfoil wake with liutex identification method. Acta Energiae Solaris Sinica, 43(10), 210–217. https://doi.org/10.19912/j.0254-0096.tynxb.2021-0343
  39. Zhang, B., Yang, P., He, C.(2024). Study on the aerodynamic and noise effects of serrated structure on NACA2418 flap airfoil. Modeling and Simulation, 13(1), 11. https://doi.org/10.12677/MOS.2024.131092
  40. Zhang, N., Jiang, J. X., Gao, B., Liu, X., Ni, D. (2020). Numerical analysis of the vortical structure and its unsteady evolution of a centrifugal pump. Renewable Energy, 155, 748–760. https://doi.org/10.1016/j.renene.2020.03.182

Last update:

No citation recorded.

Last update: 2026-07-09 02:55:34

No citation recorded.