Advanced Acoustic Assessment of Small-Scale Military-Style Nozzles with Chevrons

Kuo, Ching-Wen; Veltin, Jérémy; McLaughlin, Dennis K.

doi:10.2514/6.2010-3923

Cited by 20 publications

(22 citation statements)

References 23 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Bridges et al 12 identified issues in generating streamwise vorticity in overexpanded conditions due to the inherent contraction of the flow field at the nozzle exit. Similar findings were presented by Munday et al 13 and Kuo et al 14 Bridges et al 12 also found that the peak vorticity magnitudes roughly two diameters downstream of the nozzle were independent of initial values, though the spatial extent of the structures varied depending on the initial configuration, similar to what was presented by Opalski et al 9 Burak et al 15 noted the presence of a secondary counter rotating streamwise vortex pair in addition to the primary pair reported in most studies. Investigation of streamwise vorticity introduction into supersonic jets has typically been performed using sonic nozzles, limiting results to sonic and under expanded conditions.…”

Section: Introductionsupporting

confidence: 82%

“…Correspondingly, the three sets of vortex generators are denoted "low," "medium," and "high" throughout this work. The geometric specifics of each of these vortex generators and several other vortex generator geometries 12,14,23 are located in Table I, for comparison purposes.…”

Section: Vortex Generatorsmentioning

confidence: 99%

“…Therefore, limited investigation regarding the overexpanded regime has been performed. In fact, of the above mentioned studies, Kuo et al, 14 Bridges et al, 12 and Munday et al 13 were the only studies which investigated overexpanded operation, of which only Bridges et al 12 quantified streamwise vorticity. Consequently, additional investigation using convergent divergent nozzles is needed.…”

Section: Introductionmentioning

confidence: 96%

See 2 more Smart Citations

An experimental investigation of the flow dynamics of streamwise vortices of various strengths interacting with a supersonic jet

2014

View full text Add to dashboard Cite

The results of an experimental study involving the introduction of streamwise vorticity into a supersonic jet are presented. Both streamwise and cross stream PIV measurements of a baseline jet and three vortex generator configurations of varied penetration were acquired in the overexpanded, ideally expanded, and underexpanded regimes. Streamwise vortex pairs were shown to persist no further than two diameters downstream independent of initial magnitude. Integration of the modulus of streamwise vorticity was shown to better correlate with secondary flow field modifications than maximum values. Reductions in shock cell spacing and downstream turbulence, and increases in initial spread rate and upstream integrated turbulence were correlated with increases in streamwise vorticity for all operating conditions. Streamwise vorticity was shown to achieve opposite effects on shock strength in the over/under expanded regimes due to introduction of secondary shock structures in the underexpanded case. Additionally, limited effect on potential core length was quantified.

show abstract

Section: Introductionsupporting

confidence: 82%

Section: Vortex Generatorsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 96%

See 1 more Smart Citation

An experimental investigation of the flow dynamics of streamwise vortices of various strengths interacting with a supersonic jet

2014

View full text Add to dashboard Cite

show abstract

“…These nozzles were then designed with the same multi-faceted (12 segment) inside conical contour. More detail about these military style supersonic nozzles can be found in Kuo, Veltin, and McLaughlin [26].…”

Section: Nozzle and Fluidic Inserts Descriptionmentioning

confidence: 99%

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

Powers

Kuo

McLaughlin

et al. 2014

20th AIAA/CEAS Aeroacoustics Conference

Self Cite

View full text Add to dashboard Cite

The noise produced by supersonic, high temperature jets that exhaust from military aircraft is becoming more of a disturbance. Methods to reduce the noise produced from these jets in a realistic full-scale environment is difficult. This study describes the development and analysis of fluidic inserts for supersonic jet noise suppression. Distributed blowing within the divergent section of the military-style convergent divergent nozzle alters the shock structure of the jet in addition to creating streamwise vorticity for the reduction of mixing noise. Enhancements to the fluidic insert design have been performed along with experiments for a large number of injection parameters and core jet conditions. It has been shown that the noise reduction of the fluidic inserts is most heavily dependent on the momentum flux ratio between the injector and core jet. Maximum reductions of approximately 5.5 dB OASPL have been observed with practical mass flow rates and injection pressures. The first measurements with fluidic inserts in the presence of a forward flight stream have been performed. Optimal noise reduction occurs at similar injector parameters in the presence of forward flight. Fluidic inserts in the presence of a forward flight stream were observed to reduce the peak mixing noise by nearly 4 dB OASPL and the broadband shock-associated noise by nearly 3 dB OASPL.

show abstract

“…Experiments have shown the importance of chevron length, width and penetration on the resulting far-field acoustics [27,28]. Chevron-noise-reduction benefits achieved in moderate-scale experiments have not been duplicated in small-scale experiments where nozzle-boundary-layer separations alter chevron performance [29]. Computational and experimental flow studies have shown that increasing chevron penetration increases local radial spreading and decreases stability with downstream distance resulting in breakdown of the vorticity close to the nozzle [30].…”

Section: Introductionmentioning

confidence: 97%

An experimental investigation of overexpanded jets with chevrons

Henderson

Wernet

2015

Journal of Sound and Vibration

View full text Add to dashboard Cite

Advanced Acoustic Assessment of Small-Scale Military-Style Nozzles with Chevrons

Cited by 20 publications

References 23 publications

An experimental investigation of the flow dynamics of streamwise vortices of various strengths interacting with a supersonic jet

An experimental investigation of the flow dynamics of streamwise vortices of various strengths interacting with a supersonic jet

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

An experimental investigation of overexpanded jets with chevrons

Contact Info

Product

Resources

About