On closed-section wind-tunnel aeroacoustic experiments with a two-dimensional lifting body

Amaral, Filipe R.; Pagani, Carlos do Carmo; Himeno, Fernando Henrique Tadashi; Souza, Daniel Sampaio; Medeiros, Marcello Augusto Faraco de

doi:10.1016/j.apacoust.2018.12.029

Cited by 7 publications

(3 citation statements)

References 47 publications

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“…The greatest disagreement between computation and experiment is observed for case olAα8. Although the reason for this difference is still not clear, it may be related to excessive suction of the wind tunnel wall boundary layer, which was set based on the main-element spanwise pressure distribution (Amaral et al 2019). However, the qualitative effect of the angle of attack on the frequency and amplitude of the narrowband peaks is captured by the simulation.…”

Section: Sensitivity Of Results To Computational Parametersmentioning

confidence: 99%

“…This effect was circumvented in the reference experiments with the use of beamforming which can remove the image sources from the region of integration of the sources (Amaral et al. 2019). In the simulations, the sound is obtained only from sources on the model surface, which also does not take into account the images that could be produced by the boundaries of the computational domain.…”

Section: Unsteady Simulationsmentioning

confidence: 99%

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Dynamics of the large-scale structures and associated noise emission in airfoil slats

et al. 2019

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We investigate the slat narrowband peak noise generating mechanism. Unsteady flow data were generated by a lattice-Boltzmann-based commercial code for four configurations, accounting for variations of the airfoil angle of attack and slat overlap. Comparison with experimental results indicates that the aspects of the flow field relevant for the generation of the narrowband peaks were accurately captured. Frequency-domain proper orthogonal decomposition (POD) is applied to identify dominant large-scale structures in the frequency range dominated by the peaks. The combined use of the two POD metrics, namely, the turbulent kinetic energy in the turbulent flow region and the acoustic pressure in the far field, demonstrated that the structures most correlated with the noise resemble spanwise coherent Kelvin–Helmholtz vortices which dominate the slat cove only at the frequency of the narrowband peaks. Time evolution of the structures educed using the acoustic pressure correlation provides detailed evidence of the hydrodynamic and acoustic steps of a Rossiter-like feedback mechanism between the slat cusp and trailing edge. The combined analysis of results for the different slat configurations provides an explanation for the effect of the slat configuration on the amplitude of the narrowband peaks observed in previous studies, particularly the influence of the main-element suction peak.

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Section: Sensitivity Of Results To Computational Parametersmentioning

confidence: 99%

Section: Unsteady Simulationsmentioning

confidence: 99%

Dynamics of the large-scale structures and associated noise emission in airfoil slats

et al. 2019

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“…Studies have shown that the use of wind-tunnel boundary layer control to provide the average flow more twodimensional on the airfoil, thus reducing uncertainties on the wing effective angle of attack [32]. However, no such treatments were used in the present study, so the results are presented for the tested geometric angle of attack in the low-turbulence wind-tunnel facility at the University of Bristol.…”

Section: Airfoil and Wind-tunnel Setupmentioning

confidence: 99%

Flow characteristics of slat cove fillers

Jawahar

Theunissen

Azarpeyvand

et al. 2020

Aerospace Science and Technology

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Experimental measurements using Particle Image Velocimetry were carried out to understand the flow characteristics of a 30P30N high-lift airfoil with and without slat cove fillers. The tests were carried out for the 30P30N airfoil with a retracted chord of c = 0.35, at angles of attack of α = 6 • and 12 • , and for a chord-based Reynolds number of Re c = 7.0 × 10 5 . The wall pressure fluctuation results show that the use of slat cove fillers eliminates the slat tonal noise component. The results of the mean flow fields such as the normalized mean velocity, Reynolds stress components, and turbulent kinetic energy are presented for the baseline, half-slat cove filler, and slat cove filler configurations. The velocity contour results with streamlines showed a recirculation region within the slat cavity. The use of the half-slat cove filler reduced the size of the recirculation region and the use of the slat cove filler eliminated the recirculation region. The mean velocity and turbulent kinetic energy profiles at the slat wake showed no difference between the three tested configurations. The Particle Image Velocimetry results were further analyzed using Proper Orthogonal Decomposition. The results showed that the first two eigenmodes of the vorticity with the highest energy were contained within the slat shear layer and vortex shedding emanating from the slat cusp for the baseline case. The energy levels were distributed over the slat shear layer for the half-slat cove filler and slat cove filler configurations as the vortex shedding is suppressed by the use of the slat cove fillers.

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Improvements in closed-section wind-tunnel beamforming experiments of acoustic sources distributed along a line

2019

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On closed-section wind-tunnel aeroacoustic experiments with a two-dimensional lifting body

Cited by 7 publications

References 47 publications

Dynamics of the large-scale structures and associated noise emission in airfoil slats

Dynamics of the large-scale structures and associated noise emission in airfoil slats

Flow characteristics of slat cove fillers

Improvements in closed-section wind-tunnel beamforming experiments of acoustic sources distributed along a line

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