Experimental investigation of the far-field noise due to jet-surface interaction combined with a chevron nozzle

Bastos, Leopoldo Pacheco; Deschamps, César J.; Silva, Andrey R. da

doi:10.1016/j.apacoust.2017.06.008

Cited by 17 publications

(6 citation statements)

References 21 publications

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“…5a. This is similar to the results for chevron nozzles (Bastos et al 2017). The fact that no sound increase is observed due to the use of chevron and lobed nozzles at high frequencies for installed jet noise, as opposed to isolated jet noise, could be caused by the enhanced noise shielding effects by the flat plate when lobed and chevron jets are used.…”

Section: Effects Of Lobes On Installed Jet Noise Atsupporting

confidence: 86%

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An experimental study of the effects of lobed nozzles on installed jet noise

Lyu

Dowling

2019

Exp Fluids

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Jet noise remains a significant aircraft noise contributor, and for modern high-bypass-ratio aero-engines the strong interaction between the jet and aircraft wing leads to intensified installed jet noise. An experiment is carried out in this paper to study the effects of lobed nozzles on installed jet noise. It is found that the lobed nozzles, compared to round nozzles, have similar effects on installed jet noise for all the plate positions and Mach numbers tested. On the shielded side of the plate, the use of lobed nozzles leads to a noise reduction in the intermediate-and high-frequency regimes, which is thought to be due to a combination of enhanced jet mixing and more effective shielding effects by the flat plate. On the reflected side of the plate, noise reduction is only achieved in the intermediate frequency range; the little noise reduction or a slight noise increase observed in the high-frequency regime is likely due to enhanced jet mixing. On both sides of the plates, little noise reduction is achieved for the low-frequency noise due to the scattering of jet instability waves. This is likely to be caused by the fact that lobed nozzles cause negligible change to the dominant mode 0 (axisymmetric) jet instability waves. That the jet mean flow quickly becomes axisymmetric downstream of the jet exit could also play a role.

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Section: Effects Of Lobes On Installed Jet Noise Atsupporting

confidence: 86%

“…It is, therefore, of interest to the research community to understand how installed jet noise is affected by chevrons. A recent study was carried out by Bastos et al (2017) to examine the effects of chevron nozzles on installed jet noise. The results were compared with the installed jet noise spectra for a round nozzle.…”

Section: Introductionmentioning

confidence: 99%

An experimental study of the effects of lobed nozzles on installed jet noise

Lyu

Dowling

2019

Exp Fluids

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“…A large number of experimental and numerical studies have been carried out to understand the mechanisms of aero-acoustic noise generation (Tam et al 2008;Freund, 2001;Bahman-Jahromi et al 2019;Zuo et al 2019) and its reduction (Henderson 2010;Maizi et al 2017;Zhao et al 2018;Semlitsch et al 2019). For the simplicity and the effectivity for noise reduction, chevron nozzles (Bastos et al 2017;Xia et al 2009) are one of the most popular noise reduction strategies. They have been successfully applied by the aviation industry.…”

Section: Introductionmentioning

confidence: 99%

Compressibility Modified RANS Simulations for Noise Prediction of Jet Exhausts with Chevron

2021

JAFM

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The impact of compressibility modified RANS turbulence closures is investigated for high subsonic round and chevron jet flows with Mach = 0.9 and Re = 1.03×10 6 , including the predicted acoustic noise generation. The well-documented chevron jet flow and noise cases, namely NASA SMC000 and SMC006 are selected as the simulation configurations. Two compressibility RANS closures are considered, which are based on the k-ε turbulence model. The first type only considers the compressibility dissipation rate, and the second type accounts for three modifications of compressibility dissipation rate, pressure dilation and production limiter. The acoustic noise is calculated employing the SNGR (Stochastic Noise Generation and Radiation) method using the flow prediction of the three-dimensional RANS simulations. The results show that both of the two types of compressibility modified RANS models improve the accuracy of the mean flow and turbulence quantities. This results in more accurate jet noise predictions than with the standard RANS model. The first type modification is found to be moderate and the second type is remarkable. The noise results by the second type model, i.e. Sarkar2 model, agree with the experimental data quite well. For the mean flow field, the compressibility modified model (Sarkar2 model) estimates a shorter potential jet core, and improved predictions of the velocity in the downstream region are observed. The study demonstrates the importance of considering the compressibility modified RANS closure for the noise prediction of high-speed jets via the comparison to experimental data. Hence, the SNGR method is found to be cost effective for jet noise prediction, when compared to other approaches.

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“…At present, many operators adapt isolation working conditions when operate dry ice blasting due to high noise from the scene and some of them instruct their workers and the surrounding to wear earplugs or earmuff during the process. These techniques are not as efficient as compare to the engineering approach to curb the noise pollution in the industry in which the study was found that, the nozzle configurations play a crucial role to reduce noise generated from the system [6]. Therefore, this research focuses on different nozzle parameters of a single hose geometry by using the central composite design of an experiment to plot response surface analysis concerning the acoustic power level that represents the intensity of noise generation.…”

Section: Introductionmentioning

confidence: 99%

Response Surface Analysis of DIB Nozzle Geometry on Acoustic Power Level using Central Composite Design of Experiment

Mat

Basir

Asmuin

2021

J. Phys.: Conf. Ser.

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The critical process parameters in manufacturing dry ice blasting nozzle geometry directly related to particle jet velocity. Many studies focused on its performance without considering the noise emission due to high operating pressure. This paper, a numerical simulation study was performed using Ansys Fluent to investigate the effect of nozzle geometry of single-hose dry ice blasting on the acoustic power level. The process of modelling the two-way mass momentum and energy exchange between two phases was successfully solved iteratively in the two-way mass momentum model and the energy exchange between the two phases. It was found that the value of noise emission reaches a maximum level when the shortest convergent angle of 20° with a minimal convergent length of 50 mm and a maximum length of 300 mm is introduced. Besides, the peak value of acoustic power level swell up to 146 dB occurs at a nozzle area ratio of 20 without influencing by convergent angle and extending the divergent length highly influencing noise reduction as less than 143.5 dB for a divergent length of 700 mm.

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Experimental investigation of the far-field noise due to jet-surface interaction combined with a chevron nozzle

Cited by 17 publications

References 21 publications

An experimental study of the effects of lobed nozzles on installed jet noise

An experimental study of the effects of lobed nozzles on installed jet noise

Compressibility Modified RANS Simulations for Noise Prediction of Jet Exhausts with Chevron

Response Surface Analysis of DIB Nozzle Geometry on Acoustic Power Level using Central Composite Design of Experiment

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