Near-Field Shock/Shear-Layer Interactions in a Two-Stream Supersonic Rectangular Jet from Three-Stream Engine

Kan, Pinqing; Ruscher, Christopher J.; Lewalle, Jacques; Gogineni, Sivaram

doi:10.2514/1.j055572

Cited by 10 publications

(6 citation statements)

References 40 publications

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“…Over all, the most common paths of propagation appear to be in the free shear layer at the upper limit of the jet, in the quiescent fluid above this free shear layer, in the inner shear layer separating the primary and tertiary streams, and along the oblique shock and expansion waves in the core flow. These propagation paths are in accordance with those found in [13], and what we have expected from previous analysis. In addition, hydrodynamic events that propagate within the flow over the deck have been shown to be well correlated with acoustic emissions off the lip of the deck plate in accordance with [6], [16].…”

Section: Conclusion and Future Studiessupporting

confidence: 93%

“…8, with lag increasing from left to right and top to bottom, respectively. Similar patterns have been shown by Kan et al [13], and such a distinct pattern in the cross correlations of the schlieren field seems to support our hypothesis that strong enough regions of density variation would be objectively identifiable.…”

Section: Full-field Correlationssupporting

confidence: 92%

“…6) were defined by looking for the pixels in the schlieren field with the highest RMS noise. These points roughly corresponded to the near-field "hotspots" defined by Kan et al [13]. In an analysis of single-plane LES data, it was shown that this method proved as a useful tool in visualizing and tracking regions of high correlation as they propagate through the flow field.…”

Section: Space-time Cross Correlationsmentioning

confidence: 61%

“…To assist in the visualization of the propagation of information in the flow, we use a technique that we call spacetime correlation. This technique was developed by P. Kan and is described in detail in [13]. In this technique, a reference signal from a point of interest is cross correlated with all other points in the flow field.…”

Section: Space-time Cross Correlationsmentioning

confidence: 99%

“…We have shown that signal drift in these images can be mitigated to some degree by finding a nonlinear trendline in the data and subtracting it. By applying the space-time correlation method outlined in [13], we have been able to identify and track regions correlating well to a reference signal as they propgate through the flow field. Over all, the most common paths of propagation appear to be in the free shear layer at the upper limit of the jet, in the quiescent fluid above this free shear layer, in the inner shear layer separating the primary and tertiary streams, and along the oblique shock and expansion waves in the core flow.…”

Section: Conclusion and Future Studiesmentioning

confidence: 99%

See 4 more Smart Citations

Multi-Measurement Correlations in the Near-Field of a Complex Supersoinc Jet Using Time-Resolved Schlieren Imaging

Tenney

Coleman

Lewalle³

et al. 2017

55th AIAA Aerospace Sciences Meeting

Self Cite

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In this study, we aim to characterize the dynamics and visualize the propagation of fluctuations in the near field of a complex multi-stream jet over an aft deck plate. The flow is visualized using time resolved schlieren photography (up to 400,000 frames per second) while pressure on the aft deck plate is simultaneously sampled using Kulite pressure sensors. Time series are constructed using the schlieren photographs and conditioned to reduce the effects of signal drift. The analysis is focused in several regions identified in previous studies as dynamically interesting through their high levels of pressure variance and rich spectral content. Space-Time cross correlations are utilized to visualize propagation of fluctuations from the near field to the far field, and several propagation pathways are identified. This process is repeated for band-pass filtered schlieren signals, and a case is made for the separability of near field dynamics into distinct frequency bands.

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Section: Conclusion and Future Studiessupporting

confidence: 93%

Section: Full-field Correlationssupporting

confidence: 92%

Section: Space-time Cross Correlationsmentioning

confidence: 61%

Section: Space-time Cross Correlationsmentioning

confidence: 99%

Section: Conclusion and Future Studiesmentioning

confidence: 99%

See 3 more Smart Citations

Multi-Measurement Correlations in the Near-Field of a Complex Supersoinc Jet Using Time-Resolved Schlieren Imaging

Tenney

Coleman

Lewalle³

et al. 2017

55th AIAA Aerospace Sciences Meeting

Self Cite

View full text Add to dashboard Cite

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Investigation of flow characteristics of various-aspect-ratio rectangular nozzles with an aft deck

Chen,

Huang,

Lai

2024

Shock Waves

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This study presents an experimental and numerical investigation to characterize the plume pattern of a high-aspect-ratio rectangular convergent/divergent nozzle with an aft deck in under-expanded conditions. The function of an aft deck is to shield the infrared signal of an exhaust plume at its strongest intensity located at the immediate downstream region of the nozzle exit. However, this practice may cause undesirable plume deflection, which needs to be reduced as much as possible. The nozzle pressure ratios ranged from 2 to 4, and the effect of the nozzle exit aspect ratio was examined using wall static pressure measurements and schlieren visualization for cold flows. The experimental setup involved a 3D-printed aft deck nozzle made of acrylonitrile butadiene styrene material, which underwent surface smoothing using acetone vapor. Numerical simulations were conducted using the commercial STARCCM$$^{\mathrm {+}}$$ + software to analyze static pressure ratio variations at the aft deck. The investigation revealed that a nozzle pressure ratio of 3 induced a downward plume deflection at aspect ratio values of 6.77 and 7.54, while an increased aspect ratio of 8.35 resulted in the horizontal ejection of the plume. Moreover, at an aspect ratio of 8.35, the plume was ejected horizontally for nozzle pressure ratios ranging from 2 to 4. At a nozzle pressure ratio of 4, the flow separated from the deck without reattaching, and the plume moved horizontally with minimal deflection. The findings suggest that a combination of a high aspect ratio and sufficiently high nozzle pressure ratio can effectively reduce plume deflection.

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Numerical investigation on flow characteristics of multi-stream supersonic nozzle with serpentine configuration

Meng,

Shi,

Zhou

et al. 2024

Aerospace Science and Technology

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Near-Field Shock/Shear-Layer Interactions in a Two-Stream Supersonic Rectangular Jet from Three-Stream Engine

Cited by 10 publications

References 40 publications

Multi-Measurement Correlations in the Near-Field of a Complex Supersoinc Jet Using Time-Resolved Schlieren Imaging

Multi-Measurement Correlations in the Near-Field of a Complex Supersoinc Jet Using Time-Resolved Schlieren Imaging

Investigation of flow characteristics of various-aspect-ratio rectangular nozzles with an aft deck

Numerical investigation on flow characteristics of multi-stream supersonic nozzle with serpentine configuration

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