Hostname: page-component-78c5997874-v9fdk Total loading time: 0 Render date: 2024-11-19T06:30:15.532Z Has data issue: false hasContentIssue false
  • English
  • Français

SPOD analysis of noise-generating Rossiter modes in a slat with and without a bulb seal

Published online by Cambridge University Press:  18 March 2021

Fernando H.T. Himeno Open the ORCID record for Fernando H.T. Himeno [Opens in a new window] ,
Daniel S. Souza Open the ORCID record for Daniel S. Souza [Opens in a new window] ,
Filipe R. Amaral Open the ORCID record for Filipe R. Amaral [Opens in a new window] ,
Daniel Rodríguez Open the ORCID record for Daniel Rodríguez [Opens in a new window]  and
Marcello A.F. Medeiros Open the ORCID record for Marcello A.F. Medeiros [Opens in a new window]
Fernando H.T. Himeno*
Affiliation:
Department of Aeronautical Engineering, University of São Paulo, Av. Trabalhador São Carlense, 400, São Carlos, SP 13566-590, Brazil
Daniel S. Souza
Affiliation:
UNESP – São Paulo State University, Av. Profa. Isette Correa Fontão 505, São João da Boa Vista, São Paulo, 13876-750, Brazil
Filipe R. Amaral
Affiliation:
Department of Aeronautical Engineering, University of São Paulo, Av. Trabalhador São Carlense, 400, São Carlos, SP 13566-590, Brazil Aeronautics Institute of Technology, Praça Marechal Eduardo Gomes 50, São José dos Campos, São Paulo, 12228-900, Brazil
Daniel Rodríguez
Affiliation:
ETSIAE-UPM (School of Aeronautics), Universidad Politécnica de Madrid, Plaza del Cardenal Cisneros 3, 28040Madrid, Spain
Marcello A.F. Medeiros
Affiliation:
Department of Aeronautical Engineering, University of São Paulo, Av. Trabalhador São Carlense, 400, São Carlos, SP 13566-590, Brazil
*
†Email address for correspondence: [email protected]
Get access Rights & Permissions [Opens in a new window]

Abstract

The slat represents an important airframe noise source as it extends over almost the entire aircraft wingspan. Most studies of slat noise consider idealized geometries. However, for practical applications, several elements are installed on its cove, such as bulb seals to avoid direct contact with the main wing surface. Previous investigations of an unswept and untapered MD30P30N airfoil reported that the flow dynamics and the corresponding acoustic noise are very sensitive to the presence and location of the bulb seal. For certain locations a second recirculation bubble is created inside the slat cove and the acoustic narrowband peaks are intensified. The present paper shows that the two-bubble topology promotes the recirculation of turbulence within the slat cove. Spectral proper orthogonal decomposition analysis based on the radiated pressure intensity is used to identify the flow structures responsible for sound generation. Even though the recirculating turbulence is mostly incoherent, it interacts with the coherent Kelvin–Helmholtz vortices in the initial part of the mixing layer. Then, vortex merging and straining lead to the formation of complex vortex clusters. Our results show that the origin and evolution of these clusters are consistent with Rossiter's mechanism responsible for the narrowband peaks. The enhanced recirculation accelerates the cluster evolution leading to wider clusters and lower-frequency Rossiter modes.

JFM classification

Acoustics: Aeroacoustics Nonlinear Dynamical Systems: Low-dimensional models Vortex Flows: Vortex interactions
Type
JFM Papers
Information
Journal of Fluid Mechanics , Volume 915 , 25 May 2021 , A67
Check for updates
Copyright
© The Author(s), 2021. 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.)

References

REFERENCES

Amaral, F.R., Himeno, F.H.T., Pagani, C.C. & Medeiros, M.A.F. 2018 Slat noise from an MD30P30N airfoil at extreme angles of attack. AIAA J. 56 (3), 964–978.CrossRefGoogle Scholar
Amaral, F.R., Himeno, F.H.T., Souza, D.S., Pagani, C.C. & Medeiros, M.A.F. 2019 Effect of bubble seal on slat noise. AIAA J. 57 (4), 1608–1623.CrossRefGoogle Scholar
Bandle, L., Souza, D.S., Simões, L.G.C. & Medeiros, M.A.F. 2012 On detrimental effects of excrescences on the slat noise. In 18th AIAA/CEAS Aeroacoustics Conference (33rd AIAA Aeroacoustics Conference). AIAA Paper 2012-2099.CrossRefGoogle Scholar
Berkooz, G., Holmes, P. & Lumley, J.L. 1993 The proper orthogonal decomposition in the analysis of turbulent flows. Annu. Rev. Fluid Mech. 25 (1), 539–575.CrossRefGoogle Scholar
Bhatnagar, P.L., Gross, E.P. & Krook, M. 1954 A model for collision processes in gases. I. Small amplitude processes in charged and neutral one-component systems. Phys. Rev. 94 (3), 511–525.CrossRefGoogle Scholar
Chen, S. & Doolen, G. 1998 Lattice Boltzmann method for fluid flows. Annu. Rev. Fluid Mech. 30, 329–364.CrossRefGoogle Scholar
Chin, V., Peters, D., Spaid, F. & McGhee, R. 1993 Flowfield measurements about a multi-element airfoil at high Reynolds numbers. In 23rd Fluid Dynamics, Plasmadynamics, and Lasers Conference. AIAA Paper 1993-3137.Google Scholar
Choudhari, M. & Khorrami, M. 2007 Effect of three-dimensional shear-layer on slat cove unsteadiness. AIAA J. 45 (9), 2174–2186.CrossRefGoogle Scholar
Citriniti, J.H. & George, W.K. 2000 Reconstruction of the global velocity field in the axisymmetric mixing layer utilizing the proper orthogonal decomposition. J. Fluid Mech. 418, 137–166.CrossRefGoogle Scholar
Colonius, T. & Freund, J. 2002 POD analysis of sound generation by a turbulent jet. In 40th AIAA Aerospace Sciences Meeting and Exhibit. AIAA Paper 2002-0072.CrossRefGoogle Scholar
Dobrzynski, W. 2010 Almost 40 years of airframe noise research: what did we achieve? J. Aircraft 47 (2), 353–367.CrossRefGoogle Scholar
Dobrzynski, W. & Pott-Pollenske, M. 2001 Slat noise source studies for farfield noise prediction. In 7th AIAA/CEAS Aeroacoustics Conference and Exhibit. AIAA Paper 2001-2158.CrossRefGoogle Scholar
Guo, Y., Yamamoto, K. & Stoker, R. 2003 Component-based empirical model for high-lift system noise prediction. J. Aircraft 40 (5), 914–922.CrossRefGoogle Scholar
He, X. & Luo, L.-S. 1997 Theory of the Lattice Boltzmann method: from the Boltzmann equation to the Lattice Boltzmann equation. Phys. Rev. E 56 (6), 6811.CrossRefGoogle Scholar
Imamura, T., Enomoto, S., Yokokawa, Y. & Yamamoto, K. 2008 Three-dimensional unsteady flow computations around a conventional slat of high-lift devices. AIAA J. 46 (5), 1045–1053.CrossRefGoogle Scholar
Imamura, T., Ura, H., Yokokawa, Y. & Yamamoto, K. 2009 A far-field noise and near-field unsteadiness of a simplified high-lift-configuration model (slat). In 47th AIAA Aerospace Sciences Meeting including The New Horizons Forum and Aerospace Exposition. AIAA Paper 2009-1239.CrossRefGoogle Scholar
Jenkins, L., Khorrami, M. & Choudhari, M. 2004 Characterization of unsteady flow structures near leading-edge slat. Part I. PIV Measurements. In 10th AIAA/CEAS Aeroacoustics Conference. AIAA Paper 2004-2801.CrossRefGoogle Scholar
Khorrami, M.R., Berkman, M.E. & Choudhari, M.M. 2000 Unsteady flow computations of a slat with a blunt trailing edge. AIAA J. 38 (11), 2050–2058.CrossRefGoogle Scholar
Khorrami, M.R. & Lockard, D.P. 2010 Effects of geometric details on slat noise generation and propagation. Intl J. Aeroacoust. 9 (4), 655–678.CrossRefGoogle Scholar
Khorrami, M.R., Singer, B.A. & Berkman, M.E. 2002 Time-accurate simulations and acoustic analysis of slat free shear layer. AIAA J. 40 (7), 1284–1291.CrossRefGoogle Scholar
Kolb, A., Faulhaber, P., Drobietz, R. & Grünewald, M. 2007 Aeroacoustic wind tunnel measurements on a 2D high-lift configuration. In 13th AIAA/CEAS Aeroacoustics Conference (28th AIAA Aeroacoustics Conference). AIAA Paper 2007-3447.CrossRefGoogle Scholar
Leylekian, L., Lebrun, M. & Lempereur, P. 2014 An overview of aircraft noise reduction technologies. AerospaceLab hal-01184664, p. 15.Google Scholar
Lockard, D.P. & Choudhari, M.M. 2009 Noise radiation from a leading-edge slat. In 15th AIAA/CEAS Aeroacoustics Conference (30th AIAA Aeroacoustics Conference). AIAA Paper 2009-3101.CrossRefGoogle Scholar
Murayama, M., Nakakita, K., Yamamoto, K., Ura, H., Ito, Y. & Choudhari, M.M. 2014 Experimental study on slat noise from 30P30N three-element high-lift airfoil at JAXA hard-wall lowspeed wind tunnel. In 20th AIAA/CEAS Aeroacoustics Conference. AIAA Paper 2014-2080.CrossRefGoogle Scholar
Pagani, C.C., Souza, D.S. & Medeiros, M.A.F. 2016 Slat noise: aeroacoustic beamforming in closed-section wind tunnel with numerical comparison. AIAA J. 54 (7), 2100–2115.CrossRefGoogle Scholar
Pagani, C.C., Souza, D.S. & Medeiros, M.A.F. 2017 Experimental investigation on the effect of slat geometrical configurations on aerodynamic noise. J. Sound Vib. 394, 256–279.CrossRefGoogle Scholar
Pascioni, K.A. & Cattafesta, L.N. 2018 a An aeroacoustic study of a leading-edge slat: beamforming and far field estimation using near field quantities. J. Sound Vib. 429, 224–244.CrossRefGoogle Scholar
Pascioni, K.A. & Cattafesta, L.N. 2018 b Unsteady characteristics of a slat-cove flow field. Phys. Rev. Fluids 3, 27.CrossRefGoogle Scholar
Pott-Pollenske, M., Alvarez-Gonzalez, J. & Dobrzynski, W. 2003 Effect of slat gap/overlap on farfield radiated noise. In 9th AIAA/CEAS Aeroacoustics Conference and Exhibit. AIAA Paper 2003-3228.CrossRefGoogle Scholar
Roger, M. & Perennes, S. 2000 Low-frequency noise sources in two-dimensional high-lift devices. In 6th Aeroacoustics Conference and Exhibit. AIAA Paper 2000-1972.CrossRefGoogle Scholar
Rossiter, J.E. 1966 Wind-tunnel experiments on the flow over rectangular cavities at subsonic and transonic speeds. Tech. Rep. 3438. Aeronautical Research Council.Google Scholar
Rowley, C.W. 2002 Modeling, simulation, and control of cavity flow oscillations. PhD thesis, California Institute of Technology.Google Scholar
Sirovich, L. 1987 Turbulence and the dynamics of coherent structures. I–III. Q. Appl. Maths 45 (3), 561–590.CrossRefGoogle Scholar
Souza, D.S., Rodríguez, D., Himeno, F.H.T. & Medeiros, M.A.F. 2019 Dynamics of the large-scale structures and associated noise emission in airfoil slats. J. Fluid Mech. 875, 1004–1034.CrossRefGoogle Scholar
Souza, D.S., Rodríguez, D., Simões, L.G.C. & Medeiros, M.A.F. 2015 Effect of an excrescence in the slat cove: flow-field, acoustic radiation and coherent structures. Aerosp. Sci. Technol. 44, 108–115.CrossRefGoogle Scholar
Terracol, M., Manoha, E. & Lemoine, B. 2016 Investigation of the unsteady flow and noise generation in a slat cove. AIAA J. 54 (2), 469–489.CrossRefGoogle Scholar
Towne, A., Schmidt, O.T. & Colonius, T. 2018 Spectral proper orthogonal decomposition and its relationship to dynamic mode decomposition and resolvent analysis. J. Fluid Mech. 847, 821–867.CrossRefGoogle Scholar
Trieling, R.R., Fuentes, O.U.V. & van Heijst, G.J.F. 2005 Interaction of two unequal corotating vortices. Phys. Fluids 17 (8), 087103.CrossRefGoogle Scholar
Valarezo, W., Dominik, C., McGhee, R., Goodman, W. & Paschal, K. 1991 Multi-element airfoil optimization for maximum lift at high Reynolds numbers. In 9th Applied Aerodynamics Conference. AIAA Paper 1991-3332.CrossRefGoogle Scholar
Welch, P.D. 1967 The use of fast Fourier transform for the estimation of power spectra: A method based on time averaging over short, modified periodograms. IEEE Trans. Audio Electroacoust. 15 (2), 70–73.CrossRefGoogle Scholar
Yakhot, V. & Orszag, S.A. 1986 Renormalization group analysis of turbulence. I. Basic theory. J. Sci. Comput. 1 (1), 3–51.CrossRefGoogle Scholar