Slat noise measurement and numerical prediction in the VALIANT programme

Manoha, Eric; Terracol, Marc; Lemoine, Benoit; Griffon, Ingrid Le; Garrec, Thomas Le

doi:10.2514/6.2012-2100

Cited by 15 publications

(6 citation statements)

References 6 publications

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“…Slat noise has been studied from wind-tunnel measurements [4][5][6][7], numerical simulations [8][9][10][11][12], and flyover tests [13]: in all of which the upper slat trailing-edge appears as a potential region for noise emission. A limited number of unswept and untapered high-lift scaled models has been studied in the literature, e.g., the MD30P30N [14][15][16], the Boeing 777 two-dimensional (2-D) high lift [17], and energy-efficient transport [18,19].…”

Section: Introductionmentioning

confidence: 99%

Slat Noise from an MD30P30N Airfoil at Extreme Angles of Attack

et al. 2018

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This study investigates the slat noise of a two-dimensional scaled, unswept, and untapered MD30P30N high-lift model. The experimental data refer to aeroacoustic and aerodynamic measurements in a closed-section wind tunnel for a wide range of angles of attack (from −6 deg up to the stall; approximately at 18 deg) and Mach numbers between 0.07 and 0.1. Three slat configurations (the original MD30P30N, another with a higher slat deflection, and one with smaller slat gap and overlap) are studied experimentally. The signal processing applied to the acoustic data involves conventional beamforming enhanced by two deconvolution algorithms, namely, DAMAS and CLEAN-SC. An original variation of the beamforming cluster approach that is based on the coherence level among microphone pairs is introduced, and it improves the results obtained by DAMAS. Below −2 deg and above 12 deg angles of attack, the slat noise is very small and mostly below the wind-tunnel background noise for all configurations. Between −2 and 12 deg angles of attack, the slat noise spectra are substantially affected by the slat configuration, although it always contains a dominant low-frequency content, a midfrequency broadband noise, and a single high-frequency broad peak. Within this range, the lower angles of attack display the strongest low-frequency narrowband peaks. In fact, at lower angles of attack, the low-frequency narrowband peaks scale with a Mach power above 10.

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Section: Introductionmentioning

confidence: 99%

Slat Noise from an MD30P30N Airfoil at Extreme Angles of Attack

et al. 2018

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“…ϕ 0 • In the two other cases, it is kept at the same location. Thanks to the linearity of the Helmholtz problem, it would be possible to simulate a more extended source, for example by adding the results obtained with several source locations as in Manoha et al [26]. For the sake of brevity, only one source will be considered in the following work.…”

Section: Numerical Source Positionmentioning

confidence: 99%

Landing gear interwheel tonal noise characterization with the Boundary Element Method

Hajczak

Sanders

Druault

2019

Journal of Sound and Vibration

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Landing gear noise is mainly broadband in nature, but it can also feature some tonal contributions. Tonal noise significantly increases noise annoyance and can originate from facing cavities in landing gear wheels. The present work aims at using the Boundary Element Method (BEM) with a simple harmonic point source model to characterize the resonance between the two facing cylindrical cavities in the wheels of the generic nose landing gear LAGOON, where a flow independence of the tonal noise emission has been reported experimentally. Three configurations of increasing complexity are successively considered: a single wheel, the two facing wheels linked by an axle, and finally the whole landing gear, including the main strut. In terms of resonant frequencies, the BEM is shown to give results in very good agreement with analytical formulae and CFD/CAA computations from the literature. Some acoustic measurements are also performed for the whole LAGOON configuration and a very good agreement is observed between BEM results and the experimental database. The directivity of the resonant modes is detailed for each case and compared with success to CFD/CAA results, except for convective amplification effects. The amplification of each resonant mode is quantified through a so-called scattering factor and it is shown that the facing cavities present much sharper resonances than the single cavity, and that the presence of the main strut only increases the amplification of the axisymmetric mode. Finally, the modelisation of the interwheel space by an annular duct is discussed and a parametric study is conducted on the axle diameter. The results of this parametric study shed light on the annular duct model domain of validity while demonstrating the ability of the BEM to treat geometries of arbitrary complexity with low computational cost when analytical models are unavailable.

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“…Slat noise has been studied from wind tunnel measurements 5,6,7,8,9 , numerical simulations 10,11,12,13,14,15 , and flyover tests 16 . Wind tunnel experiments using scaled high-lift models have revealed a slat noise signature featuring from broadband to tonal noise components.…”

Section: Introductionmentioning

confidence: 99%

Experiments on Slat Noise from -6° to 18° Angles of Attack

Amaral

Pagani

Himeno

et al. 2016

46th AIAA Fluid Dynamics Conference

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This study focuses on investigating the slat noise of a two-dimensional scaled, unswept and untapered, MD30P30N high-lift model. The database refers aeroacoustic and aerodynamic measurements in a closed-section wind tunnel for a wide range of angles of attack, namely from −6 • and 18 • , and Mach number ranging from 0.07 to 0.1. Aeroacoustic measurements were carried using a wall-mounted microphone array. The signal processing applied to the acoustic data involved conventional beamforming enhanced by two deconvolution algorithms, DAMAS and CLEAN-SC. Suction-based wall boundary-layer control was applied to provide a more two dimensional flow over the model span. Chord-wise and span-wise static pressure measurements were performed. Slat noise spectra revel low-frequency tones, broadband noise and a single broad tone in the higher frequency range. The results show all slat noise components are strongly affected by wing angle of attack. The low-frequency tones vanish at lower negative wing angles of attack but reach their higher level at lower positive angles of attack. The tones level variation within a narrow range of angles of attack may be over 10 dB/Hz. Overall, the dominant part in the slat noise spectra reduces as the wing angle of attack increases, rendering higher frequency noise components potential contributors to the overall noise.

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Slat noise measurement and numerical prediction in the VALIANT programme

Cited by 15 publications

References 6 publications

Slat Noise from an MD30P30N Airfoil at Extreme Angles of Attack

Slat Noise from an MD30P30N Airfoil at Extreme Angles of Attack

Landing gear interwheel tonal noise characterization with the Boundary Element Method

Experiments on Slat Noise from -6° to 18° Angles of Attack

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