Abstract
Airframe became a relevant source of noise in commercial aircrafts because of the introduction of high by-pass ratio turbofans. The slat is one of the most important airframe noise source, since it represents a source distributed along the wing span. The flow mechanism responsible for noise generation is not completely understood yet. Time-accurate Lattice-Boltzmann simulations were carried out in order to deliver flow data for the calculations of coherent structures in the slat cove by means of the Proper Orthogonal Decomposition (POD) technique. The first two POD-modes are dominated by mixing-layer like structures. Power Spectral Density of the amplitude of these leading POD-functions present the highest level at frequencies that are dominant in the spectrum of far-field acoustic fluctuations.
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References
B. S. Aflalo, L. G. C. Simões, R. G. Silva, and M. A. F. Medeiros. Comparative analysis of turbulence models for slat noise source calculations employing unstructured meshes. AIAA Paper 2010–3838, 2010.
G. A. Brès, F. Pérot, and F. Freed. A Ffowcs Williams-Hawkings solver for Lattice-Boltzmann based computational aeroacoustics. AIAA Paper 2010–3711, 2010.
M. M. Choudhari, M. R. Khorrami, D. P. Lockard, H. L. Atkins, and G. M. Lilley. Slat cove noise modeling: A posteriori analysis of unsteady RANS simulations. AIAA Paper 2002–2468, 2002.
M. M. Choudhari, D. P. Lockard, M. G. Macaraeg, B. A. Singer, C. L. Streett, G. R. Neubert, R. W. Stoker, J. R. Underbrink, M. E. Berkman, M. R. Khorrami, and S. S. Sadowski. Aeroacoustic experiments in the Langley low-turbulence pressure tunnel. Technical Report NASA TM 2002–211432, 2002.
W. Dobrzynski. Almost 40 years of airframe noise research: What did we achieve? Journal of Aircraft, 47(2), 2010.
W. Dobrzynski and M. Pott-Pollenske. Slat noise source studies for farfield noise prediction. AIAA Paper 2001–2158, 2001.
Fares E (2006) Unsteady flow simulation of the Ahmed reference body using a Lattice Boltzmann approach. Computers and Fluids 35:940–950
Holmes P, Lumley J, Berkooz G (1996) Turbulence, Coherent Structures. Cambridge University Press, Dynamical Systems and Symmetry
T. Imamura, H. Ura, Y. Yokokawa, and K. Yamamoto. A far-field noise and near-field unsteadiness of a simplified high-lift-configuration model (Slat). AIAA Paper 2009–1239, 2009.
L. N. Jenkins, M. R. Khorrami, and M. M. Choudhari. Characterization of unsteady flow structures near leading-edge slat: Part I. PIV measurements. AIAA Paper 2004–2801, 2004.
M. R. Khorrami, M. M. Choudhari, and L. N. Jenkins. Characterization of unsteady flow structures near leading-edge slat: Part II. 2D computations. AIAA Paper 2004–2802, 2004.
Khorrami MR, Singer BA, Berkman ME (2002) Time-accurate simulations and acoustic analysis of slat free-shear-layer. AIAA Journal 40(7):1284–1291
A. Kolb, P. Faulhaber, R. Drobietz, and M. Grünewald. Aeroacoustic wind tunnel measurements on a 2D high-lift configuration. AIAA Paper 2007–3447, 2007.
D. P. Lockard and M. M. Choudhari. Noise radiation from a leading-edge slat. AIAA Paper 2009–3101, 2009.
D. P. Lockard and M. M. Choudhari. The effect of cross flow on slat noise. AIAA Paper 2010–3835, 2010.
D. P. Lockard and M. M. Choudhari. The influence of realistic Reynolds numbers on slat noise simulations. AIAA Paper 2012–2101, 2012.
M. Pott-Pollenske, J. Delfs, and J. Reichenberger. A testbed for large scale and high Reynolds number airframe noise research. AIAA Paper 2013–2260, 2013.
L. G. C. Simões, D. S. Souza, and M. A. F. Medeiros. On the small effect of boundary layer thicknesses on slat noise. AIAA Paper 2011–2906, 2011.
L. Sirovich. Chaotic dynamics of coherent structures. Parts I-III. Quarterly Applied Math., XLV(3), 1987.
D. S. Souza, D. Rodríguez, and M. A. F. Medeiros. Effect of an excrescence in the slat cove: Flow-field, acoustic radiation and coherent structures. Aerospace Science and Technology, 2013.
D. S. Souza, D. Rodríguez, and M. A. F. Medeiros. A study of the sources of slat noise using proper orthogonal decomposition. AIAA Paper 2013–2163, 2013.
M. Wei and J. B. Freund. A noise-controlled free shear flow. Journal Fluid Mechanics, 546, 2006.
Acknowledgments
D. S. Souza acknowledges funding from CAPES—Coordenação de Aperfeiçoamento de Pessoal de Nível Superior. M. A. F. Medeiros acknowledges support from CNPq/Brasil—Conselho Nacional de Desenvolvimento Científico e Tecnológico. Support of the Marie Curie Grant PIRSES-GA-2009-247651 “FP7-PEOPLE-IRSES: ICOMASEF, Instability and Control of Massively Separated Flows” is gratefully acknowledged. D. Rodríguez acknowledges funding from the Marie Curie-COFUND UNITE programme.
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Souza, D.S., Rodríguez, D., de Medeiros, M.A.F. (2015). Proper Orthogonal Decomposition Analysis of Noise Generation Mechanisms in the Slat Cove. In: Theofilis, V., Soria, J. (eds) Instability and Control of Massively Separated Flows. Fluid Mechanics and Its Applications, vol 107. Springer, Cham. https://doi.org/10.1007/978-3-319-06260-0_35
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DOI: https://doi.org/10.1007/978-3-319-06260-0_35
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