Hostname: page-component-77f85d65b8-lfk5g Total loading time: 0 Render date: 2026-03-27T11:32:34.176Z Has data issue: false hasContentIssue false
  • English
  • Français

Manipulation of mid- and high-frequency wall-pressure sources by streamwise finlets

Published online by Cambridge University Press:  21 February 2025

Zhihang Pan  and
Qingqing Ye Open the ORCID record for Qingqing Ye [Opens in a new window]
Zhihang Pan
Affiliation:
State Key Laboratory of Fluid Power and Mechatronic Systems, Department of Mechanics, Zhejiang University, Hangzhou 310027, PR China
Qingqing Ye*
Affiliation:
State Key Laboratory of Fluid Power and Mechatronic Systems, Department of Mechanics, Zhejiang University, Hangzhou 310027, PR China
*
†Email address for correspondence: qingqing_ye@zju.edu.cn
Get access Rights & Permissions [Opens in a new window]

Abstract

In the present research, the effect of streamwise finlets on the coherent structures of a turbulent boundary layer and their relation with pressure fluctuations and trailing-edge noise is investigated experimentally over a NACA0018 airfoil. A synthetic measurement is performed using time-resolved particle image velocimetry, wall-pressure transducers and a far-field microphone. The finlets induce strong momentum transport within the boundary layer, leading to the formation of a detached shear layer and backward flow separation. A strong velocity deficit is produced close to the wall. The instantaneous flow organisation reveals the formation of hairpin-like vortices on top of the finlets and spanwise rollers in the near-wall separation bubble. The newly generated vortices disrupt the turbulent coherent structures of the untreated case remarkably. An overall lift-up process of the unsteady turbulent structures is produced, bringing the most energetic turbulent structures away from the wall and reducing the near-wall shear stress. The spatial and temporal relation between instantaneous unsteady flow features and wall-pressure fluctuations is analysed quantitatively. A notable reduction of the correlation and coherence intensity in the mid- and high-frequency bands is achieved due to the modification of the turbulent structures. The former frequency ranges agree with that of the pressure fluctuations and far-field noise suppression, revealing the noise-reduction mechanisms.

JFM classification

Acoustics: Aeroacoustics Boundary Layers: Boundary layer structure Boundary Layers: Boundary layer control

Information

Type
JFM Papers
Information
Journal of Fluid Mechanics , Volume 1005 , 25 February 2025 , A8
Check for updates
Copyright
© The Author(s), 2025. Published by Cambridge University Press

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

Article purchase

Temporarily unavailable

References

Abe, H. 2017 Reynolds-number dependence of wall-pressure fluctuations in a pressure-induced turbulent separation bubble. J. Fluid Mech. 833, 563–598.CrossRefGoogle Scholar
Adrian, R.J. 2007 Hairpin vortex organization in wall turbulence. Phys. Fluids 19 (4), 041301.CrossRefGoogle Scholar
Adrian, R.J., Meinhart, C.D. & Tomkins, C.D. 2000 Vortex organization in the outer region of the turbulent boundary layer. J. Fluid Mech. 422, 1–54.CrossRefGoogle Scholar
Afshari, A., Azarpeyvand, M., Dehghan, A.A., Szőke, M. & Maryami, R. 2019 Trailing-edge flow manipulation using streamwise finlets. J. Fluid Mech. 870, 617–650.CrossRefGoogle Scholar
Ali, S.A.S., Azarpeyvand, M. & Da Silva, C.R.I. 2018 Trailing-edge flow and noise control using porous treatments. J. Fluid Mech. 850, 83–119.Google Scholar
Allen, J.M. & Tudor, D.M. 1969 Charts for interpolation of local skin friction from experimental turbulent velocity profiles. NASA Tech. Rep. NASA-SP-3048.Google Scholar
Amiet, R.K. 1976 Noise due to turbulent flow past a trailing edge. J. Sound Vib. 47 (3), 387–393.CrossRefGoogle Scholar
Ananthan, V.B. & Akkermans, R.A.D. 2023 Trailing edge noise reduction using bio-inspired finlets. J. Sound Vib. 549, 117553.CrossRefGoogle Scholar
Antonia, R.A. 1981 Conditional sampling in turbulence measurement. Annu. Rev. Fluid Mech. 13 (1), 131–156.CrossRefGoogle Scholar
Avallone, F., Pröbsting, S. & Ragni, D. 2016 Three-dimensional flow field over a trailing-edge serration and implications on broadband noise. Phys. Fluids 28 (11), 117101.CrossRefGoogle Scholar
Bodling, A. & Sharma, A. 2019 Numerical investigation of noise reduction mechanisms in a bio-inspired airfoil. J. Sound Vib. 453, 314–327.CrossRefGoogle Scholar
Bouard, R. & Coutanceau, M. 1980 The early stage of development of the wake behind an impulsively started cylinder for $40< Re< 104$. J. Fluid Mech. 101 (3), 583–607.CrossRefGoogle Scholar
Brooks, T.F., Pope, D.S. & Marcolini, M.A. 1989 Airfoil self-noise and prediction. NASA Tech. Rep. NASA-RP-1218.Google Scholar
Bull, M.K. 1967 Wall-pressure fluctuations associated with subsonic turbulent boundary layer flow. J. Fluid Mech. 28 (4), 719–754.CrossRefGoogle Scholar
Burgmann, S. & Schröder, W. 2008 Investigation of the vortex induced unsteadiness of a separation bubble via time-resolved and scanning PIV measurements. Exp. Fluids 45 (4), 675–691.CrossRefGoogle Scholar
Chandran, D., Monty, J.P. & Marusic, I. 2020 Spectral-scaling-based extension to the attached eddy model of wall turbulence. Phys. Rev. Fluids 5 (10), 104606.CrossRefGoogle Scholar
Chong, T.P. & Joseph, P.F. 2013 An experimental study of airfoil instability tonal noise with trailing edge serrations. J. Sound Vib. 332 (24), 6335–6358.CrossRefGoogle Scholar
Clark, I., Baker, D., Alexander, W.N., Devenport, W.J., Glegg, S.A., Jaworski, J. & Peake, N. 2016 Experimental and theoretical analysis of bio-inspired trailing edge noise control devices. AIAA Paper 2016-3020.CrossRefGoogle Scholar
Clark, I.A., Alexander, W.N., Devenport, W., Glegg, S., Jaworski, J.W., Daly, C. & Peake, N. 2017 Bioinspired trailing-edge noise control. AIAA J. 55 (3), 740–754.CrossRefGoogle Scholar
Clauser, F.H. 1954 Turbulent boundary layers in adverse pressure gradients. J. Aeronaut. Sci. 21 (2), 91–108.CrossRefGoogle Scholar
Farabee, T.M. & Casarella, M.J. 1984 Effects of surface irregularity on turbulent boundary layer wall pressure fluctuations. J. Vib. Acoust. 106 (3), 343–350.CrossRefGoogle Scholar
Feng, Z. & Ye, Q. 2023 Turbulent boundary layer over porous media with wall-normal permeability. Phy. Fluids 35 (9), 095111.CrossRefGoogle Scholar
Fiscaletti, D., Luesutthiviboon, S., Avallone, F. & Casalino, D. 2022 Streamwise fences for the reduction of trailing-edge noise in a NACA633018 airfoil. AIAA Paper 2022-1925.CrossRefGoogle Scholar
Garcia-Sagrado, A., Hynes, T. & Hodson, H. 2006 Experimental investigation into trailing edge noise sources. AIAA Paper 2006-2476.CrossRefGoogle Scholar
Geyer, T., Sarradj, E. & Fritzsche, C. 2010 Measurement of the noise generation at the trailing edge of porous airfoils. Exp. Fluids 48, 291–308.CrossRefGoogle Scholar
Ghaemi, S. & Scarano, F. 2011 Counter-hairpin vortices in the turbulent wake of a sharp trailing edge. J. Fluid Mech. 689, 317–356.CrossRefGoogle Scholar
Ghaemi, S. & Scarano, F. 2013 Turbulent structure of high-amplitude pressure peaks within the turbulent boundary layer. J. Fluid Mech. 735, 381–426.CrossRefGoogle Scholar
Gibeau, B. & Ghaemi, S. 2021 Low- and mid-frequency wall-pressure sources in a turbulent boundary layer. J. Fluid Mech. 918, A18.CrossRefGoogle Scholar
Giepman, R.H.M., Schrijer, F.F.J. & Van Oudheusden, B.W. 2014 Flow control of an oblique shock wave reflection with micro-ramp vortex generators: effects of location and size. Phys. Fluids 26 (6), 066101.CrossRefGoogle Scholar
Giepman, R.H.M., Schrijer, F.F.J. & Van Oudheusden, B.W. 2018 A parametric study of laminar and transitional oblique shock wave reflections. J. Fluid Mech. 844, 187–215.CrossRefGoogle Scholar
Goody, M. 2004 Empirical spectral model of surface pressure fluctuations. AIAA J. 42 (9), 1788–1794.CrossRefGoogle Scholar
Gstrein, F., Zang, B. & Azarpeyvand, M. 2021 a Investigations on the application of various surface treatments for trailing edge noise reduction on a flat plate. AIAA Paper 2021-2263.CrossRefGoogle Scholar
Gstrein, F., Zang, B. & Azarpeyvand, M. 2023 Trailing-edge noise reduction through finlet-induced turbulence. J. Fluid Mech. 959, A24.CrossRefGoogle Scholar
Gstrein, F., Zang, B., Mayer, Y. & Azarpeyvand, M. 2021 b Turbulence characteristics of finlet treatments applied for trailing edge noise reduction of a NACA0012 airfoil. AIAA Paper 2021-2112.CrossRefGoogle Scholar
Gstrein, F., Zang, B., Mayer, Y.D. & Azarpeyvand, M. 2022 Airfoil trailing-edge noise reduction by application of finlets. AIAA J. 60 (1), 236–248.Google Scholar
Harun, Z., Monty, J.P., Mathis, R. & Marusic, I. 2013 Pressure gradient effects on the large-scale structure of turbulent boundary layers. J. Fluid Mech. 715, 477–498.CrossRefGoogle Scholar
Howe, M.S. 1978 A review of the theory of trailing edge noise. J. Sound Vib. 61 (3), 437–465.CrossRefGoogle Scholar
Humble, R.A. 2008 Unsteady flow organization of a shock wave/boundary layer interaction. PhD thesis, Delft University of Technology, the Netherlands.CrossRefGoogle Scholar
Hutchins, N. & Marusic, I. 2007 Evidence of very long meandering features in the logarithmic region of turbulent boundary layers. J. Fluid Mech. 579, 1–28.CrossRefGoogle Scholar
Hwang, H.G. & Lee, J.H. 2018 Secondary flows in turbulent boundary layers over longitudinal surface roughness. Phys. Rev. Fluids 3 (1), 014608.CrossRefGoogle Scholar
Hwang, Y.F., Bonness, W.K. & Hambric, S.A. 2009 Comparison of semi-empirical models for turbulent boundary layer wall pressure spectra. J. Sound Vib. 319 (1–2), 199–217.CrossRefGoogle Scholar
Kim, J. 1983 On the structure of wall-bounded turbulent flows. Phys. Fluids 26, 2088.CrossRefGoogle Scholar
Kiya, M. & Sasaki, K. 1983 Structure of a turbulent separation bubble. J. Fluid Mech. 137, 83–113.CrossRefGoogle Scholar
Kobashi, Y. & Ichijo, M. 1986 Wall pressure and its relation to turbulent structure of a boundary layer. Exp. Fluids 4 (1), 49–55.CrossRefGoogle Scholar
Leclercq, D., Jacob, M., Louisot, A. & Talotte, C. 2001 Forward-backward facing step pair-aerodynamic flow, wall pressure and acoustic characterisation. AIAA Paper 2001-2249.Google Scholar
Lee, J., Lee, J.H., Choi, J.-I. & Sung, H.J. 2014 Spatial organization of large- and very-large-scale motions in a turbulent channel flow. J. Fluid Mech. 749, 818–840.CrossRefGoogle Scholar
Lee, S. 2018 Empirical wall-pressure spectral modeling for zero and adverse pressure gradient flows. AIAA J. 56 (5), 1818–1829.CrossRefGoogle Scholar
Lee, S., Ayton, L., Bertagnolio, F., Moreau, S., Chong, T.P. & Joseph, P. 2021 Turbulent boundary layer trailing-edge noise: theory, computation, experiment, and application. Prog. Aerosp. Sci. 126, 100737.CrossRefGoogle Scholar
Liu, X., Zang, B. & Azarpeyvand, M. 2022 Wake-aerofoil interaction noise control with trailing-edge serrations. Exp. Therm. Fluid Sci. 130, 110510.CrossRefGoogle Scholar
Lumley, J.L. 1979 Computational modeling of turbulent flows. Adv. Appl. Mech. 18, 123–176.CrossRefGoogle Scholar
Medjnoun, T., Vanderwel, C. & Ganapathisubramani, B. 2020 Effects of heterogeneous surface geometry on secondary flows in turbulent boundary layers. J. Fluid Mech. 886, A31.CrossRefGoogle Scholar
Millican, A.J., Clark, I., Devenport, W.J. & Alexander, W.N. 2017 Owl-inspired trailing edge noise treatments: acoustic and flow measurements. AIAA Paper 2017-1177.CrossRefGoogle Scholar
Moreau, S. & Roger, M. 2024 Turbomachinery noise review. Intl J. Turbomach. Propul. Power 9 (1), 11.CrossRefGoogle Scholar
Na, Y. & Moin, P. 1998 The structure of wall-pressure fluctuations in turbulent boundary layers with adverse pressure gradient and separation. J. Fluid Mech. 377, 347–373.CrossRefGoogle Scholar
Naka, Y., Stanislas, M., Foucaut, J.-M., Coudert, S., Laval, J.-P. & Obi, S. 2015 Space–time pressure–velocity correlations in a turbulent boundary layer. J. Fluid Mech. 771, 624–675.CrossRefGoogle Scholar
Palani, S., Paruchuri, C.C., Joseph, P., Karabasov, S.A., Utyuzhnikov, S., Devenport, W.J. & Glegg, S.A. 2022 Comparison of finlet rails and fences for trailing edge noise reduction in NACA0012 aerofoil, p. 3015. AIAA Paper 2022-3015.CrossRefGoogle Scholar
Roger, M., Moreau, S. & Guédel, A. 2006 Vortex-shedding noise and potential-interaction noise modeling by a reversed sears’ problem. AIAA Paper 2006-2607.CrossRefGoogle Scholar
Rozenberg, Y., Robert, G. & Moreau, S. 2012 Wall-pressure spectral model including the adverse pressure gradient effects. AIAA J. 50 (10), 2168–2179.CrossRefGoogle Scholar
Shi, Y. & Kollmann, W. 2021 Wall-modeled large-eddy simulation of a trailing-edge serration–finlet configuration. AIP Adv. 11 (6), 065222.CrossRefGoogle Scholar
Shi, Y. & Lee, S. 2020 Numerical study of 3-d finlets using Reynolds-averaged Navier–Stokes computational fluid dynamics for trailing edge noise reduction. Intl J. Aeroacoust. 19 (1–2), 95–118.CrossRefGoogle Scholar
Showkat Ali, S.A., Azarpeyvand, M., Szőke, M. & Ilário da Silva, C.R. 2018 Boundary layer flow interaction with a permeable wall. Phys. Fluids 30 (8), 085111.CrossRefGoogle Scholar
de Silva, C.M., Chandran, D., Baidya, R., Hutchins, N. & Marusic, I. 2020 Periodicity of large-scale coherence in turbulent boundary layers. Intl J. Heat Fluid Flow 83, 108575.CrossRefGoogle Scholar
Sun, Z., Schrijer, F.F.J., Scarano, F. & van Oudheusden, B.W. 2014 Decay of the supersonic turbulent wakes from micro-ramps. Phys. Fluids 26 (2), 025115.CrossRefGoogle Scholar
Tanarro, Á., Vinuesa, R. & Schlatter, P. 2020 Effect of adverse pressure gradients on turbulent wing boundary layers. J. Fluid Mech. 883, A8.CrossRefGoogle Scholar
Thomas, A.S.W. & Bull, M.K. 1983 On the role of wall-pressure fluctuations in deterministic motions in the turbulent boundary layer. J. Fluid Mech. 128, 283–322.CrossRefGoogle Scholar
Ye, Q., Schrijer, F.F.J. & Scarano, F. 2016 Boundary layer transition mechanisms behind a micro-ramp. J. Fluid Mech. 793, 132–161.CrossRefGoogle Scholar
Ye, Q., Schrijer, F.F.J. & Scarano, F. 2018 On Reynolds number dependence of micro-ramp-induced transition. J. Fluid Mech. 837, 597–626.CrossRefGoogle Scholar
Yoon, M., Hwang, J., Yang, J. & Sung, H.J. 2020 Wall-attached structures of streamwise velocity fluctuations in an adverse-pressure-gradient turbulent boundary layer. J. Fluid Mech. 885, A12.CrossRefGoogle Scholar
Zang, B., Mayer, Y.D. & Azarpeyvand, M. 2020 A note on the pressure–velocity correlation and coherence normalisation. Exp. Fluids 61 (8), 186.CrossRefGoogle Scholar
Supplementary material: File

Pan and Ye supplementary movie 1

Normalized instantaneous streamwise velocity (u/U∞) for the untreated case.
Download Pan and Ye supplementary movie 1(File)
File 7.8 MB
Supplementary material: File

Pan and Ye supplementary movie 2

Normalized instantaneous streamwise velocity fluctuations (u′/U∞) for the untreated case.
Download Pan and Ye supplementary movie 2(File)
File 7 MB
Supplementary material: File

Pan and Ye supplementary movie 3

Normalized instantaneous streamwise velocity (u/U∞) for the S3-F case.
Download Pan and Ye supplementary movie 3(File)
File 7.3 MB
Supplementary material: File

Pan and Ye supplementary movie 4

Normalized instantaneous streamwise velocity fluctuations (u′/U∞) for the S3-F case.
Download Pan and Ye supplementary movie 4(File)
File 6.8 MB
Supplementary material: File

Pan and Ye supplementary movie 5

Normalized instantaneous streamwise velocity (u/U∞) for the S3-M case.
Download Pan and Ye supplementary movie 5(File)
File 7.9 MB
Supplementary material: File

Pan and Ye supplementary movie 6

Normalized instantaneous streamwise velocity fluctuations (u′/U∞) for the S3-M case.
Download Pan and Ye supplementary movie 6(File)
File 6.6 MB