A preliminary semi-empirical approach for CROR noise modeling

Quaglia, Michael; Moreau, Stéphane; Roger, Michel; Fernando, Rasika

doi:10.2514/6.2016-2743

Cited by 4 publications

(4 citation statements)

References 28 publications

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“…Most studies focus on CROR noise sources. For instance, among numerous works, some experimental, 1-3 numerical 4,5 and modelling 6,7 works on isolated CROR aim to improve the understanding of the noise generation mechanisms and the accuracy of their noise prediction. Some studies also include the mitigation of CROR noise by modifying the flow generating the aeroacoustic sources.…”

Section: Introductionmentioning

confidence: 99%

Prediction of the acoustic shielding by aircraft empennage for contra-rotating open rotors

Sanders

Mincu

Vitagliano

et al. 2017

International Journal of Aeroacoustics

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This paper presents a numerical study of the acoustic shielding of aeroengine noise by the aircraft structure. More specifically, the engines considered are contra-rotating open rotors in pusher mode which are installed at the rear of the aircraft. Several empennage designs and engine positions are evaluated. An original method for the calculation of engine noise installation effects is presented and its application to contra-rotating open rotor propulsion is demonstrated. It is based on the weak coupling between computational fluid dynamics, an integral method based on Lighthill's analogy for the calculation of acoustic radiation, and on a boundary element method for the calculation of the acoustic diffraction by the aircraft fuselage and empennage. The prediction of a pylon-installed (isolated) contra-rotating open rotor noise directivity is presented and compared to equivalent wind-tunnel measurements. In both cases, the simulation and experiment are performed at 1:7 scale. In addition, the installation effect of the wind-tunnel, being nonanechoic, is also assessed with the numerical approach presented. Finally, for each aircraft configuration of interest, equipped with two rear contra-rotating open rotors, the predicted noise impact on the ground is evaluated. Of these, the contra-rotating open rotor mounted above an L-tail empennage is found to be the most beneficial configuration in terms of acoustic shielding.

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Section: Introductionmentioning

confidence: 99%

Prediction of the acoustic shielding by aircraft empennage for contra-rotating open rotors

Sanders

Mincu

Vitagliano

et al. 2017

International Journal of Aeroacoustics

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“…The tip vortex is first extracted from the simulation and fitted with a Batchelor vortex model (a Lamb–Oseen model in the vortex tangential plane with an additional Gaussian-shape axial velocity), which was found to closely represent the evolution of the actual front rotor tip vortex. 43,46 The tip vortex is then subtracted from the shear flow to yield the front rotor wake only. Both contributions are then evaluated and compared to experimental results in Figure 12.…”

Section: Cror Noisementioning

confidence: 99%

“…The validation of the model was first assessed with Blandeau’s canonical blade configuration by Quaglia et al. 46 The model has then been applied to the above realistic FL05/AL05 CROR approach configuration, using the turbulent variables of the u-RANS simulation to reconstruct a von Kármán spectrum for the front rotor wake impinging turbulence. Figure 13 shows the PSD of the acoustic pressure at distance R = 20 m in two directions, upstream of the CROR ( Θ=150°) in Figure 13(a) and above the CROR ( Θ=90°) in Figure 13(b).…”

Section: Cror Noisementioning

confidence: 99%

Advanced noise modeling for future propulsion systems

Moreau

Roger

2018

International Journal of Aeroacoustics

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In order to meet noise specifications for future foreseen aircraft propulsion systems, such as for ultrahigh bypass ratio turbofans and contra-rotating open rotors, the dominant turbomachinery noise mechanisms need to be modeled accurately at an early design stage. Two novel methods are presented here, which could significantly improve the existing analytical noise models. For the high-solidity ultrahigh bypass ratio, a mode-matching technique based on a modal expansion of acoustic and vortical variables in each subdomain of a blade row is shown to accurately reproduce sound generation and propagation in two-dimensional bifurcated channels and in three-dimensional annular unstaggered flat-plate cascades. For the low solidity contra-rotating open rotors, several extensions to Amiet's compressible isolated airfoil theory are coupled with Curle's and Ffowcs Williams and Hawkings' acoustic analogy in the frequency domain within a strip theory framework, to yield both far-field tonal and broadband noise. Including sweep in both tonal and broadband noise models is shown to significantly improve the comparison with experiments on a stationary swept airfoil in a uniform turbulent stream and on a realistic contrarotating open rotor geometry at approach conditions.

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“…Many methods for predicting contra-rotating propeller interaction tone noise have used frequency-domain sound radiation formulae. Examples of such analytic or hybrid analytic-numerical noise prediction methods are described in Hanson (1985), Parry (1988), Whitfield, Mani & Gliebe (1990a,b), Carazo, Roger & Omais (2011), , Zachariadis, Hall & Parry (2011), Kingan & Sureshkumar (2014), Grasso et al (2014), Ekoule et al (2015Ekoule et al ( , 2017, Quaglia et al (2016Quaglia et al ( , 2017, Moreau & Roger (2018) and Kingan & Parry (2019a,b). In addition to these, primarily numerical approaches which utilise a frequency-domain sound radiation formulation include the methods described by Peters & Spakovszky (2010), Sharma & Chen (2013) and Envia (2015).…”

Section: Introductionmentioning

confidence: 99%