The Influence of Realistic Reynolds Numbers on Slat Noise Simulations

Lockard, David P.; Choudhari, Meelan M.

doi:10.2514/6.2012-2101

Cited by 14 publications

(7 citation statements)

References 33 publications

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“…Moreover, wind tunnel measurements by Herr et al. (2015) with Reynolds numbers up to 5 million, and Navier–Stokes simulations by Lockard & Choudhari (2012) at real-scale Reynolds numbers show similar series of narrowband low-frequency peaks. Therefore, the relevance of the narrowband peaks to full-scale slat noise remains an open question.…”

Section: Introductionmentioning

confidence: 80%

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: Introductionmentioning

confidence: 80%

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

et al. 2019

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“…The rare experiments on swept wing noise, carried out in DNW for the A320 wing [1], did not reveal significant narrowband peaks in the slat noise. Whether this is due to the effect of sweep, larger Reynolds numbers or a feature of the specific geometry remains an open question, despite a number of works on this subject [4][5][6][7][8][9]. This paper experimentally investigates the effect of sweep of a wing with the deployed high lift devices on noise mitigation due to the chevron edge of the slat.…”

Section: Introductionmentioning

confidence: 94%

Effect of sweep on chevron slat noise

Kopiev¹,

Zaitsev²,

Belyaev³

2013

19th AIAA/CEAS Aeroacoustics Conference

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Experimental investigation of the effect of sweep on slat noise has been performed for small-scale (1:18) models, which indicates that sweep can significantly modify airframe noise spectra. The new method of airframe noise mitigation based on the concept of chevron geometry for the slat's lower egde, which has been previously proved efficient for 2D wing models, has been assessed for the swept wing. It has been demonstrated that the method is effective for narrowband peak mitigation both for swept wing and 2D wing.

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“…Pott-Pollenske, Delfs & Reichenberger (2013) also reported that the slat noise spectra at Re c = 5 × 10 6 did not contain any narrowband peaks. However, Lockard & Choudhari (2012) and Herr et al (2015) found that narrowband peaks robustly existed in the slat noise spectra at Re c = 1.2 × 10 7 and at Re c = 5 × 10 6 , respectively. Although whether narrowband peaks exist in the slat noise spectra at Re c ∼ 10 7 is an open question, massive benchmark investigations captured narrowband peaks in the slat noise spectra at Re c ∼ 10 6 (Murayama et al 2014;Choudhari & Lockard 2015;Li et al 2017Li et al , 2018aPascioni & Cattafesta 2018a).…”

Section: Introductionmentioning

confidence: 97%