The Design, Development and Commissioning of a Test Capability for Studying Cruise Noise

Harper-Bourne, Marcus; Wrighton, C.

doi:10.2514/6.2005-3051

Cited by 5 publications

(1 citation statement)

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“…The complexity of the flow is increased with respect to single-stream jets: The presence of the inner shear-layer between the fan and core jet flows leads to supplementary interactions between shock cells and shear layers and to intricate propagation effects in subsonic and supersonic flows with temperature gradients. A number of model-scale investigations have focused on BBSAN with forward-flight effects at cruise condition [11,12,13,14]. Promising shock noise models have also been proposed [15,16,17,18].…”

Section: Introductionmentioning

confidence: 99%

Understanding and Reduction of Cruise Jet Noise at Aircraft Level

Huber

Bulté

Laurendeau³

et al. 2014

International Journal of Aeroacoustics

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Within the LINFaN research project, Airbus and Rolls-Royce have jointly investigated the acoustic impact of supersonic jet noise on the fuselage of an Airbus A340 equipped with Rolls-Royce Trent 500 engines in cruise conditions. The main results are presented in this paper. The influence of chevron fan nozzles designed to reduce cruise jet noise on the rear fuselage is investigated. The characterization of both the acoustic field and the aerodynamic flow is carried out. The acoustic data are obtained from a microphone array on the rear fuselage. After specific data de-noising, the acoustic spectra radiated on the fuselage by only the right inner engine are estimated. Beamforming acoustic maps are also computed to localize the jet noise sources. Besides, the supersonic jet flows are characterized by RANS CFD approach. For the baseline round nozzle, the acoustic results show the presence of two distinct broadband shock-associated noise contributions on the fuselage. The first pattern is observed in the far aft section of the fuselage for Strouhal numbers based on the jet mixing diameter and velocity between St = 4 and 6. The other pattern, around St = 1, radiates preferably forward. In addition, the high frequency source is located between 4 and 5 mixed jet diameters past the secondary nozzle exhaust plane, while the low frequency source is located farther downstream between 7 and 8 mixed jet diameters. Shock-associated noise is usually associated with the interaction between shock cells and turbulent shear-layers. We postulate that the high-frequency noise component results from the interaction between the shock-cells in the secondary flow and the inner shear-layer, while the low-frequency component is due to the interaction between shock cells and the outer shear-layer. This interpretation is consistent with two observations. The first observation is a strong modification of the measured high frequency noise when the engine is pushed to high power. At

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Section: Introductionmentioning

confidence: 99%

Understanding and Reduction of Cruise Jet Noise at Aircraft Level

Huber

Bulté

Laurendeau³

et al. 2014

International Journal of Aeroacoustics

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Prediction of Flowfield and Acoustic Signature of a Coaxial Jet Using RANS-Based Methods and Large-Eddy Simulation

Andersson

Eriksson

2008

International Journal of Aeroacoustics

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The feasibility of using large-eddy simulation (LES) for jet noise predictions has been discussed in several publications. The vast majority of these studies are, however, restricted to fairly simple geometries and moderate Reynolds numbers flows. Recent studies have shown that LES-based methods can be used for realistic flows and complex geometries with promising results. With continuously increased computer capacity and with the possibility to perform computations in parallel on PC-clusters, the possibility of using LES for industrial applications is increasing. However, although, the complexity of configurations for which LES may be used is approaching that of a real jet engine, due to high demands for computational power and long turnover times LES is still not feasible for industrial use. For low-noise nozzle design, engineering tools with short turnover time, accurate enough for prediction of noise trends are therefore needed. In the development of such methods, LES can provide data suitable for method validation. In the present work, the high-subsonic flow in an axisymmetric coaxial nozzle/jet configuration is studied. Flowfield predictions obtained using an axisymmetric RANS solver for compressible flows and predicted acoustic signature obtained using a method based on RANS and Lighthill's acoustic analogy are compared with flowfield and radiated sound predictions obtained using LES combined with Kirchhoff surface integration. In the predicted flow statistics, the most noticeable difference between RANS and LES results is that the RANS calculation gives somewhat lower levels of turbulence kinetic energy in the shear layers in the near-nozzle regions and hence the LES jet mixes somewhat faster and thus the potential core region is shorter in this simulation. NOMENCLATURE Latin symbols c speed of sound C p specific heat at constant pressure aeroacoustics volume 7 • number 1 • 2008-pages 23-40 Prediction of flowfield and acoustic signature of a coaxial jet using RANS-based methods and large-eddy simulation

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