Supersonic Jet Noise Reduction by Nozzle Fluidic Inserts with Simulated Forward Flight

Powers, Russell W.; Kuo, Ching-Wen; McLaughlin, Dennis K.; Morris, Philip J.

doi:10.2514/6.2014-2474

Cited by 23 publications

(7 citation statements)

References 36 publications

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“…The microphones used are 1/8 in (3.2 mm) pressure field microphones type 40DP from GRAS. More details on the data acquisition and processing, including all spectral corrections to obtain the presented lossless acoustic spectra can be found in prior publications, (see Kuo et al 6 and Powers et al 11 ).…”

Section: B Experimental Approachmentioning

confidence: 99%

Prediction, Experiments and Optimization of High-Speed Jet Noise Reduction Using Fluidic Inserts

Morris¹,

McLaughlin

Powers

et al. 2014

50th AIAA/ASME/SAE/ASEE Joint Propulsion Conference

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This paper describes several components of a study examining noise reduction in high speed heated jets using fluidic inserts. This noise reduction technology is based on the ideas developed by Seiner and his colleagues at NASA Langley Research Center and the University of Mississippi 1 . That approach was based on the introduction of corrugated seals into the diverging section of a convergent divergent nozzle. These corrugations change the effective area ratio so that the jet operates closer to an on-design condition and reduces broadband shock-associated noise. In addition, the corrugations generate streamwise vorticity that breaks up the large scale structures in the jet and reduces mixing noise. The idea behind fluidic inserts, described by Morris et al. 2 is to generate an equivalent effect with low levels of flow injection in the diverging section of the nozzle. This has the considerable advantage that the fluidic inserts can be controlled actively for maximum noise reduction and performance benefits. The present paper describes recent developments in the optimization of the fluidic insert concept. Flow and noise experiments, including the effect of forward flight are described. Numerical simulations are performed to characterize the flow features generated by the fluidic inserts as well as to develop measures of flow characteristics that can be related to the observed noise changes. These measures can be used to develop a cost function in a design optimization procedure.

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Section: B Experimental Approachmentioning

confidence: 99%

Prediction, Experiments and Optimization of High-Speed Jet Noise Reduction Using Fluidic Inserts

Morris¹,

McLaughlin

Powers

et al. 2014

50th AIAA/ASME/SAE/ASEE Joint Propulsion Conference

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“…With rapid prototyping, a few nozzles are built at a time, and then the injection pressure is varied, rather than having a large nozzle design matrix. For the purposes of this study, results from only fluidic insert configurations (including hole locations, diameters, and flow-rates) that have been shown to be effective with free jets [10] will be shown.…”

Section: Fluidic Insert Nozzlesmentioning

confidence: 99%

“…The research reported in this paper describes further development made to an approach described in earlier publications [2,[9][10][11], on nozzles with hardwalled corrugations replaced by fluidic insert corrugations. This is achieved by carefully distributed blowing in the divergent section of the nozzle.…”

Section: Introductionmentioning

confidence: 95%

Noise Reduction with Fluidic Inserts in Supersonic Jets Exhausting Over a Simulated Aircraft Carrier Deck

Powers

McLaughlin

Morris

2015

21st AIAA/CEAS Aeroacoustics Conference

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A developing noise reduction method for supersonic exhaust jets was studied in a model scale aircraft carrier environment. Acoustic experiments of model exhaust jets with (and without) distributed blowing, producing "fluidic inserts", were performed. The model carrier environment consisted of a ground plane of adjustable distance below the jet, and a simulated jet blast deflector similar to those found in practice. Measurements were performed with far-field microphones, near-field microphones, and unsteady pressure sensors. The constructive and destructive interference that results from the interaction of the direct and reflected sound waves was observed and compared with results from free jets. The noise reduction of fluidic inserts in a realistic carrier deck environment with steering of the "quiet planes" was examined. The overall sound pressure level in heat-simulated jets was reduced by 3-5 dB depending on the specific angle and ground plane height. Jets impinging upon a modeled jet blast deflector were tested in addition to jets solely in the presence of the carrier deck. Observed modifications to the acoustic field from the presence of the jet blast deflector included downstream acoustic shielding and low frequency augmentation. The region of maximum noise radiation for heat-simulated jets from nozzles with fluidic inserts impinging on the jet blast deflector was reduced in overall sound pressure level by 4-7 dB. This region includes areas where aircraft carrier personnel are located.

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“…It is a variable area ratio nozzle capable of adjusting its throat to exit area ratio based on the flight regime. This ratio is chosen as 1.295 to match previous experiments [11][12][13][14]. This is typical of takeoff conditions and corresponds to a design Mach number (M d ) of 1.65.…”

Section: Description Of Nozzle Variantsmentioning

confidence: 99%

Effect of fluid injection on turbulence and noise reduction of a supersonic jet

Prasad

Morris

2019

Phil. Trans. R. Soc. A.

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Supersonic jets, such as the ones used in high-performance military aircraft, have both downstream and upstream noise components due to the large-scale turbulent structures and the presence of shock cells in the jet plume. The fluid insert technology is a noise reduction method that has been shown to effectively reduce both these noise components. This paper analyses the unsteady flow changes associated with different fluid insert configurations with a goal of helping to understand the detailed noise reduction mechanisms. Using direct cross-correlations of the near-field data with the far-field microphone signals, it is found that even the use of a single injector as a fluid insert helps break up the large-scale structures of the flow. However, a more azimuthally distributed blowing is required to reduce the upstream broadband shock-associated noise (BBSAN). Addition of upstream injectors at each azimuthal location further enhances the BBSAN reduction. Decomposition of the jet flow-field into hydrodynamic and acoustic modes shows that fluid insert nozzles reduce the amplitude and convection speed of the coherent acoustic mode in the plane of highest noise reduction. This article is part of the theme issue ‘Frontiers of aeroacoustics research: theory, computation and experiment’.

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Supersonic Jet Noise Reduction by Nozzle Fluidic Inserts with Simulated Forward Flight

Cited by 23 publications

References 36 publications

Prediction, Experiments and Optimization of High-Speed Jet Noise Reduction Using Fluidic Inserts

Prediction, Experiments and Optimization of High-Speed Jet Noise Reduction Using Fluidic Inserts

Noise Reduction with Fluidic Inserts in Supersonic Jets Exhausting Over a Simulated Aircraft Carrier Deck

Effect of fluid injection on turbulence and noise reduction of a supersonic jet

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