Turbulence Associated with Broadband Shock Noise in Hot Jets

Bridges, Jackie; Wernet, Mark P.

doi:10.2514/6.2008-2834

Cited by 64 publications

(76 citation statements)

References 11 publications

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“…These studies report a strong screech attenuation, but their slots are bound to damage the BBSAN component as well due to their large depth. A nozzle with shallow notches cut into the lip was used at NASA (e.g., by Bridges and Wernet [32]) to study the BBSAN specifically. It has the advantage of reducing alterations to the jet structure.…”

Section: Introductionmentioning

confidence: 99%

Broadband Shock-Associated Noise in Screeching and Non-Screeching Underexpanded Supersonic Jets

2013

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The effect of screech tones on the broadband shock-associated noise of underexpanded jets is investigated experimentally. Screech is removed by means of a notched nozzle, and the properties of the broadband shockassociated noise in the screech-free configuration are compared to that in a screeching flow. It is first demonstrated that the suppressing technique used is nonintrusive in that it does not alter the shock-cell structure of the jet plume. It is then shown that screech has an effect on the aerodynamics of the jet, which induces changes in the broadband shockassociated noise. Indeed, screech accelerates the damping of the shock-cell pattern, leading to an attenuation of the broadband shock-associated noise and a shifting of this noise component to higher frequencies. Moreover, a tuning between the peak frequency of the broadband shock-associated noise and the screech frequency is observed. It is also deduced from the directivity of the broadband shock-associated noise in the far field that the convective velocity in the shear layer is modified in the presence of screech tones.

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Section: Introductionmentioning

confidence: 99%

Broadband Shock-Associated Noise in Screeching and Non-Screeching Underexpanded Supersonic Jets

2013

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“…As noted above, this is associated with large amplitude jet column undulation caused by screech, originally documented by Glass [39] and more recently Bridges and Wernet [40]. Consequently, direct comparison between the baseline jet's potential core length and the investigated chevron cases was difficult as screech amplitude was drastically reduced by all of the chevron configurations as shown above in Fig.…”

Section: Flow Fieldmentioning

confidence: 96%

“…11. The presence of relatively large amplitude screech at the design condition is known to increase the levels of downstream turbulence as compared to the expected levels from a non-screeching axisymmetric jet [40]. Consequently, comparison to the baseline results at the design condition is difficult, as the chevron configurations all but eliminated screech.…”

Section: Flow Fieldmentioning

confidence: 99%

“…Application of chevrons was able to reduce the screech amplitude in comparison to the baseline jet, independent of azimuthal angle and jet Mach number. An important feature to note is the large amplitude screech observed for the baseline configuration at M j ¼1.36 and 1.50, which is a feature that has been known to lead to flow field modifications [39,40] as discussed below. Comparison of the azimuthal arrangements to the standard chevron configuration generally shows slightly worse performance in the overexpanded regime and similar or better in the ideally and under expanded conditions.…”

Section: Acoustic Fieldmentioning

confidence: 99%

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Impact of chevron spacing and asymmetric distribution on supersonic jet acoustics and flow

Heeb

Gutmark

Kailasanath

2016

Journal of Sound and Vibration

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“…The effect of propulsion system design choices including integration with the airframe can be methodically, and effectively addressed within such a framework. Most recently, Mendez et al (2009Mendez et al ( , 2010 have successfully applied unstructured LES scheme of Shoeybi et al (2009) and predicted the noise emitted from supersonic jets and compared the result to the experiments carried out by Bridges & Wernet (2008). An important lesson learned from previous research on computational aeroacousitcs is that a numerical method suitable for accurate prediction of noise requires extra care in many different aspects.…”

Section: Introductionmentioning

confidence: 99%

Unstructured Large Eddy Simulation Technology for Prediction and Control of Jet Noise

Khalighi

Ham

Moin

et al. 2010

Volume 1: Aircraft Engine; Ceramics; Coal, Biomass and Alternative Fuels; Education; Electric Power; Manufacturing Materials An

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Development of concepts for reduction of jet noise has relied heavily on expensive experimental testing of various nozzle designs. For example, the design of nozzle serrations (chevron) and internal mixer/ejector nozzles have relied largely on laboratory and full-scale testing. Without a deeper understanding of the sources of high-speed jet noise it is very difficult to effectively design configurations that reduce the noise and maintain other performance metrics such as nozzle thrust. In addition, the high complexity of the flow limits the success of a parametric black-box optimization.

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Turbulence Associated with Broadband Shock Noise in Hot Jets

Cited by 64 publications

References 11 publications

Broadband Shock-Associated Noise in Screeching and Non-Screeching Underexpanded Supersonic Jets

Broadband Shock-Associated Noise in Screeching and Non-Screeching Underexpanded Supersonic Jets

Impact of chevron spacing and asymmetric distribution on supersonic jet acoustics and flow

Unstructured Large Eddy Simulation Technology for Prediction and Control of Jet Noise

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