Fan Flow Deflection in Simulated Turbofan Exhaust
TLDR
Fan flow deflection for jet noise reduction was applied to subscale nozzles simulating the geometry and exhaust conditions of separate-flow turbofan engines as mentioned in this paper, and two types of deflectors were tested, one comprising two pairs of vanes internal to the fan and the other consisting of a wedge positioned outside the fan duct.Abstract:
Fan flow deflection for jet noise reduction was applied to subscale nozzles simulating the geometry and exhaust conditions of separate-flow turbofan engines. Two types of deflectors were tested, one comprising two pairs of vanes internal to the fan duct and the other consisting of a wedge positioned outside the fan duct. The noise reduction achieved by the vanes was strong in the downward direction and moderate in the sideline direction. The wedge generated significant attenuation in both directions. The acoustic results are consistent with the measured distortion of the mean velocity field. An approach for the treatment ofnonaxisymmetricjets vis-a-vis perceived noise prediction is introduced.read more
Citations
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Proceedings ArticleDOI
Reduction of Radiation Efficiency in High-Speed Jets
TL;DR: The Lighthill acoustic analogy indicates that substantial noise reduction is possible in high-speed jets by reducing the radiation efficiency as mentioned in this paper, which is caused primarily by the reduction in radiation efficiency.
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Computation of High-Speed Coaxial Jets with Fan Flow Deflection
TL;DR: In this paper, the authors present a computational study, validated by mean-flow experiments, of a dual-stream nozzle simulating the exit conditions of a supersonic turbofan engine with noise-suppressing fan flow deflectors.
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Modelling of noise reduction in complex multistream jets
TL;DR: In this article, the authors present a low-order prediction scheme for the noise change in multistream jets when the nozzle geometry is altered from a known baseline, using a Reynolds-averaged Navier-Stokes (RANS) solver.
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Computational Analyses of Offset-Stream Nozzles for Noise Reduction
TL;DR: In this paper, the authors performed a series of simulations on two offset stream nozzles for reducing the amount of turbulence on the lower side of the jet plume and showed good performance.
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Influence of swirl number on jet noise reduction using flat vane swirlers
P. Balakrishnan,K.N. Srinivasan +1 more
TL;DR: In this article, the authors proposed to use a swirling flow surrounding a circular free jet to reduce low frequency noise, irrespective of the free jet's nozzle pressure ratio, by using six flat vanes fixed in an annular passage with vane angles ranging from 0 to 50°.
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