Assessment of Noise Reduction Concepts for Leading-Edge Slat Noise

Zhang, Yang; O’Neill, Adam; Cattafesta, Louis N.; Pascioni, Kyle A.; Choudhari, Meelan M.; Khorrami, Mehdi R.; Lockard, David P.; Turner, Travis L.

doi:10.2514/6.2018-3461

Cited by 13 publications

(6 citation statements)

References 22 publications

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“…This shows that for the H-SCF configuration, even though the size of the cavity is reduced and the acoustic feedback mechanism that gives rise to the tonal behaviour has been eliminated, the spanwise correlation length remains the same as that of the Baseline airfoil. This behaviour was also observed by Zhang et al [42].…”

Section: Spanwise Coherencesupporting

confidence: 87%

“…Several experimental and computational studies were conducted in the past decade to investigate and reduce the broadband noise arising from within the slat cove region by casing the recirculation region [32][33][34][35][36][37][38][39][40][41][42]. The results showed that the use of slat cove filler (SCF) leads to a marginal reduction of the broadband noise and elimination of the tonal peaks at all the instances.…”

Section: Introductionmentioning

confidence: 99%

“…The final optimized SCF profile showed a reduction in noise while maintaining the aerodynamic performance. In a very recent study, Zhang et al [42] showed that the use of passive treatments on the slat, such as slat extensions, gap fillers and cove fillers, exhibit minimal detrimental effect on the mean pressure distribution of the high-lift device. They also showed that the proposed passive devices suppress the slat cavity tonal peaks, as well as shifting them to higher frequencies.…”

Section: Introductionmentioning

confidence: 99%

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Aerodynamic and aeroacoustic performance of high-lift airfoil fitted with slat cove fillers

Jawahar

Ali

Azarpeyvand

et al. 2020

Journal of Sound and Vibration

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Experimental measurements were carried out to assess the aerodynamic and aeroacoustic performance of an MDA 30P30N airfoil fitted with two different types of slat cove fillers. The aerodynamic results are presented for lift and drag measurements and mean surface pressure measurements, while the aeroacoustic results are presented for the near-field surface pressure fluctuations and far-field noise measurement. The flow measurement results show that there is no significant difference in the aerodynamic lift and drag between the tested cases, however, the slat cove filler configurations exhibit a much better lift-to-drag performance. The pressure coefficient results show that the use of slat cove fillers leads to a slight decrease in the suction peak over the main-element of the airfoil. In order to better understand the flow-field and the noise generation mechanism of the airfoil with slat cove fillers, simultaneous near-field and far-field noise measurements were carried out. The result shows that the use of the slat cove filler can generally lead to a significant reduction of the broadband noise and eliminate the characteristic tonal noise generated by the slat. The directivity pattern and the overall sound pressure level of the radiated noise have shown that a significant noise reduction can be achieved with the applications of the slat cove fillers. The multiple tonal phenomena generated by the slat were also analysed using the continuous wavelet transform method and higher order spectral analysis methods.

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Section: Spanwise Coherencesupporting

confidence: 87%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Aerodynamic and aeroacoustic performance of high-lift airfoil fitted with slat cove fillers

Jawahar

Ali

Azarpeyvand

et al. 2020

Journal of Sound and Vibration

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“…1b) [17]. This concept has been shown to be effective at noise reduction both experimentally [20][21][22][23][24] and computationally [25,26]. Alternative noise mitigation attempts include extended blade seals [27], brushes [28,29], mass injection [30], and the slat-gap filler † † [31,32].…”

mentioning

confidence: 99%

Design of Shape-Adaptive Deployable Slat-Cove Filler for Airframe Noise Reduction

Arena¹,

Groh²,

Pirrera

et al. 2021

Journal of Aircraft

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“…Several successful studies [35][36][37][38][39][40][41][42][43][44][45] were carried out over the two decades to reduce the characteristic noise arising from the slat. They achieved this by enclosing the recirculation within the slat cavity.…”

mentioning

confidence: 99%

Intermittency analysis of high-lift airfoil with slat cove fillers

Jawahar

Meloni

Azarpeyvand

et al. 2020

Aiaa Aviation 2020 Forum

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Experimental measurements were carried out to assess the aeroacoustic characteristics of 30P30N airfoil fitted with two different types of slat cove fillers at the aeroacoustic facility at the University of Bristol. The results are presented for the angle of attack α = 18 • at a free-stream velocity of U ∞ = 30 m/s which corresponds to a chord-based Reynolds number of Re c = 7 × 10 • . Simultaneous measurements of the unsteady surface pressure were made at several locations in the vicinity of slat cove and at the far-field location to gain a deeper understanding of the slat noise generation mechanism. The results are analyzed using a higher-order statistical approach to determine the nature of the broadband hump seen at low-frequency for the 30P30N high-lift airfoil observed in recent studies and also to further understand the tone generation mechanism within the slat cavity. A series of cross-correlation and coherence of the unsteady pressure measurements are carried out to identify and isolate the low-frequency hump. Wavelet analysis is performed to investigate the nature of the slat-wing resonant intermittent events in both time and frequency domains. The far-field noise measurement results showed that significant noise reduction can be achieved by the use of slat cove fillers. A series of far-field and near-field correlation are also presented to show the propagated noise from the slat.

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Assessment of Noise Reduction Concepts for Leading-Edge Slat Noise

Cited by 13 publications

References 22 publications

Aerodynamic and aeroacoustic performance of high-lift airfoil fitted with slat cove fillers

Aerodynamic and aeroacoustic performance of high-lift airfoil fitted with slat cove fillers

Design of Shape-Adaptive Deployable Slat-Cove Filler for Airframe Noise Reduction

Intermittency analysis of high-lift airfoil with slat cove fillers

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