Hostname: page-component-cd9895bd7-p9bg8 Total loading time: 0 Render date: 2024-12-28T21:33:27.298Z Has data issue: false hasContentIssue false
  • English
  • Français

On the noise prediction for serrated leading edges

Published online by Cambridge University Press:  03 August 2017

B. Lyu Open the ORCID record for B. Lyu [Opens in a new window]  and
M. Azarpeyvand
B. Lyu*
Affiliation:
Department of Engineering, University of Cambridge, Cambridge CB2 1PZ, UK
M. Azarpeyvand*
Affiliation:
Department of Mechanical Engineering, University of Bristol, Bristol BS8 1TR, UK
*
†Email addresses for correspondence: [email protected], [email protected]
†Email addresses for correspondence: [email protected], [email protected]
Get access Rights & Permissions [Opens in a new window]

Abstract

An analytical model is developed for the prediction of noise radiated by an aerofoil with leading-edge serration in a subsonic turbulent stream. The model makes use of Fourier expansion and Schwarzschild techniques in order to solve a set of coupled differential equations iteratively and express the far-field sound power spectral density in terms of the statistics of incoming turbulent upwash velocity. The model has shown that the primary noise-reduction mechanism is due to the destructive interference of the scattered pressure induced by the leading-edge serrations. It has also shown that in order to achieve significant sound reduction, the serration must satisfy two geometrical criteria related to the serration sharpness and hydrodynamic properties of the turbulence. A parametric study has been carried out and it is shown that serrations can reduce the overall sound pressure level at most radiation angles, particularly at small aft angles. The sound directivity results have also shown that the use of leading-edge serration does not significantly change the dipolar pattern of the far-field noise at low frequencies, but it changes the cardioid directivity pattern associated with radiation from straight-edge scattering at high frequencies to a tilted dipolar pattern.

JFM classification

Acoustics: Aeroacoustics Acoustics: Noise control
Type
Papers
Information
Journal of Fluid Mechanics , Volume 826 , 10 September 2017 , pp. 205 - 234
Check for updates
Copyright
© 2017 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.)

References

Allampalli, V., Hixon, R., Nallasamy, M. & Sawyer, S. D. 2009 High-accuracy large-step explicit Runge–Kutta (HALE-RK) schemes for computational aeroacoustics. J. Comput. Phys. 228 (10), 3837–3850.Google Scholar
Amiet, R. K. 1975 Acoustic radiation from an airfoil in a turbulent stream. J. Sound Vib. 41 (4), 407–420.CrossRefGoogle Scholar
Amiet, R. K. 1976a High frequency thin-airfoil theory for subsonic flow. AIAA J. 14 (8), 1076–1082.Google Scholar
Amiet, R. K. 1976b Noise due to turbulent flow past a trailing edge. J. Sound Vib. 47 (3), 387–393.Google Scholar
Amiet, R. K. 1978 Effect of the incident surface pressure field on noise due to turbulent flow past a trailing edge. J. Sound Vib. 57, 305–306.Google Scholar
Atassi, H. M., Fang, J. & Patrick, S. 1993 Direct calculation of sound radiated from bodies in nonuniform flows. J. Fluids Engng 115 (4), 573–579.Google Scholar
Brooks, T. F., Pope, D. S. & Marcolini, M. A.1989 Airfoil self-noise and prediction. NASA Reference Publication 1218. NASA.Google Scholar
Bushnell, D. M. & Moore, K. J. 1991 Drag reduction in nature. Annu. Rev. Fluid Mech. 23, 65–79.Google Scholar
Chaitanya, P., Narayanan, S., Joseph, P. & Kim, J. W. 2016 Leading edge serration geometries for significantly enhanced leading edge noise reductions. In Proceedings of the 22nd AIAA/CEAS Aeroacoustics Conference. American Institute of Aeronautics and Astronautics. AIAA 2016-2736.Google Scholar
Curle, N. 1955 The influence of solid boundaries upon aerodynamic sound. Proc. R. Soc. Lond. A 231, 505–514.Google Scholar
Devenport, W. J., Staubs, J. K. & Glegg, S. A. L. 2010 Sound radiation from real airfoils in turbulence. J. Sound Vib. 329 (17), 3470–3484.Google Scholar
Fish, F. E. & Battle, J. M. 1995 Hydrodynamic design of the humpback whale flipper. J. Morphol. 225, 51–60.Google Scholar
Fish, F. E., Howle, L. E. & Murray, M. M. 2008 Hydrodynamic flow control in marine mammals. Integr. Compar. Biol. 48 (6), 788–800.Google Scholar
Gill, J., Zhang, X. & Joseph, P. 2013 Symmetric airfoil geometry effects on leading edge noise. J. Acoust. Soc. Am. 134 (4), 2669–2680.Google Scholar
Goldstein, M. E. 1978 Unsteady vortical and entropic distortions of potential flows round arbitrary obstacles. J. Fluid Mech. 89, 443–468.Google Scholar
Goldstein, M. E. & Atassi, H. 1976 A complete second-order theory for the unsteady flow about an airfoil due to a periodic gust. J. Fluid Mech. 74, 741–765.Google Scholar
Graham, J. M. R. 1970 Similarity rules for thin aerofoils in non-stationary subsonic flows. J. Fluid Mech. 43 (04), 753–766.Google Scholar
Hansen, K. L., Kelso, R. M. & Dally, B. B. 2011 Peformance variations of leading-edge tubercles for distinct airfoil profiles. AIAA J. 49 (1), 185–194.Google Scholar
Hixon, R., Mankbadi, R. R., Scott, J. R., Sawyer, S. & Nallasamy, M. 2006 Application of a nonlinear computational aeroacoustics code to the gust-airfoil problem. AIAA J. 44 (2), 323–328.Google Scholar
Johari, H., Henoch, C. W., Custodio, D. & Levshin, A. 2007 Effects of leading-edge protuberances on airfoil performance. AIAA J. 45, 2634–2642.CrossRefGoogle Scholar
Hansen, K., Kelso, R. & Doolan, C. 2012 Reduction of flow induced airfoil tonal noise using leading edge sinusoidal modifications. Acoust. Austral. 40 (3), 172–177.Google Scholar
Kim, J. W., Haeri, S. & Joseph, P. F. 2016 On the reduction of aerofoil-turbulence interaction noise associated with wavy leading edges. J. Fluid Mech. 792, 526–552.Google Scholar
Kovasznay, L. S. G. 1953 Turbulence in supersonic flow. J. Aeronaut. Sci. 20 (10), 657–674.CrossRefGoogle Scholar
Landahl, M. 1961 Unsteady Transonic Flow. Pergamon.Google Scholar
Lau, A. S. H., Haeri, S. & Kim, J. W. 2013 The effect of wavy leading edges on aerofoil-gust interaction noise. J. Sound Vib. 332 (24), 6234–6253.Google Scholar
Lyu, B., Azarpeyvand, M. & Sinayoko, S. 2015 A trailing-edge noise model for serrated edges. In Proceedings of the 21st AIAA/CEAS Aeroacoustics Conference. American Institute of Aeronautics and Astronautics. AIAA 2015-2362.Google Scholar
Lyu, B., Azarpeyvand, M. & Sinayoko, S. 2016a Noise prediction for serrated leading-edges. In Proceedings of the 22nd AIAA/CEAS Aeroacoustics Conference. American Institute of Aeronautics and Astronautics. AIAA 2016-2740.Google Scholar
Lyu, B., Azarpeyvand, M. & Sinayoko, S. 2016b Noise prediction for serrated trailing edges. J. Fluid Mech. 793, 556–588.Google Scholar
Miklosovic, D. S. & Murray, M. M. 2004 Leading-edge tubercles delay stall on humpback whale (Megaptera novaeangliae) flippers. Phys. Fluids 16 (5), 39–42.Google Scholar
Myers, M. R. & Kerschen, E. J. 1995 Influence of incidence angle on sound generation by airfoil interacting with high-frequency gusts. J. Fluid Mech. 292, 271–304.Google Scholar
Myers, M. R. & Kerschen, E. J. 1997 Influence of camber on sound generation by airfoils interacting with high-frequency gusts. J. Fluid Mech. 353, 221–259.Google Scholar
Narayanan, S., Chaitanya, P., Haeri, S., Joseph, P., Kim, J. W. & Placsek, C. 2015 Airfoil noise reductions through leading edge serrations. Phys. Fluids 27, 025109.CrossRefGoogle Scholar
Paterson, R. W. & Amiet, R. K.1976 Acoustic radiation and surface pressure response of an airfoil due to incident turbulence. Tech. Rep. CR-2733, NASA, Washington, DC.CrossRefGoogle Scholar
Pedro, H. T. C. & Kobayashi, M. H. 2008 Numerical study of stall delay on humpback whale flippers. In Proceedings of the 46th AIAA Aerospace Sciences Meeting and Exhibit. American Institute of Aeronautics and Astonautics. AIAA 2008-2584.Google Scholar
Roger, M. & Carazo, A. 2010 Blade-geometry considerations in analytical gust-airfoil interaction noise models. In Proceedings of the 16th AIAA/CEAS Aeroacoustics Conference. American Institute of Aeronautics and Astronautics. AIAA 2010-3799.Google Scholar
Roger, M. & Moreau, S. 2005 Back-scattering correction and further extensions of Amiet’s trailing-edge noise model. Part 1. Theory. J. Sound Vib. 286 (1–2), 477–506.Google Scholar
Roger, M., Schram, C. & Santana, L. D. 2013 Reduction of airfoil turbulence-impingement noise by means of leading-edge serrations and/or porous materials. In Proceedings of the 19th AIAA/CEAS Aeroacoustics Conference. American Institute of Aeronautics and Astronautics. AIAA 2013-2108.Google Scholar
Sears, W. R. 1941 Some aspects of non-stationary airfoil theory and its practical application. J. Aeronaut. Sci. 8, 104–108.Google Scholar
Sinayoko, S., Azarpeyvand, M. & Lyu, B. 2014 Trailing edge noise prediction for rotating serrated blades. In Proceedings of the 20th AIAA/CEAS Aeroacoustics Conference. American Institute of Aeronautics and Astronautics. AIAA 2014-3296.Google Scholar
Soderman, P. T.1972 Aerodynamics effects of leading-edge serrations on a two-dimensional airfoil. NASA Tech. Mem. X-2643. NASA.Google Scholar
Süli, E. & Mayers, D. 2003 An Introduction to Numerical Analysis. Cambridge University Press.CrossRefGoogle Scholar
Tsai, C. T. & Kerschen, E. J.1990 Influence of airfoil nose radius on sound generated by gust interactions. In Proceedings of the 13th AIAA Aeroacoustic Conference. American Institute of Aeronautics and Astronautics. AIAA 90-3912.Google Scholar
Turner, J. M. & Kim, J. W. 2016 Towards understanding aerofoils with dual-frequency wavy leading edges interacting with vortical distrubances. In Proceedings of the 22nd AIAA/CEAS Aeroacoustics Conference. American Institute of Aeronautics and Astronautics. AIAA 2016-2951.Google Scholar