Characterization of Bleedless Shockwave Boundary Layer Interaction Control for High Speed Intakes

Khobragade, Nikhil; Gustavsson, Jonas; Kumar, Rajan; Kirby, Simon; Birch, Trevor; L., Chi; Taylor, R

doi:10.2514/6.2020-2091

Cited by 4 publications

(2 citation statements)

References 12 publications

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“…The present computational analysis is informed by a complimentary experimental study of the corresponding inlet configurations, that have been previously reported in Khobragade et al (2020). Selected experimental results are also utilized in this study to validate the simulations wherever possible.…”

Section: Methodsmentioning

confidence: 99%

“…Upon modifying the interaction region geometry using a BFS smaller than the incoming boundary layer thickness, Li & Liu (2019) observed that the height of the separation bubble reduces, and the reflected shock gets suppressed. An application of geometry-based SBLI control in supersonic intakes can be found in the experimental studies by Khobragade et al (2020). It addresses the effects of a baseline geometry with a faceted junction, and a modified geometry with a notched junction, on unstart characteristics of a Mach 3 intake, earlier shown in figure 1(a).…”

Section: Introductionmentioning

confidence: 99%

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Flow instabilities and impact of ramp–isolator junction on shock–boundary-layer interactions in a supersonic intake

2022

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Boundary layer instabilities and shock–boundary-layer interactions (SBLIs) critically affect the performance and safe operation of mixed-compression air intakes. We present a computational study anchored in companion experiments, to evaluate the multimodal mechanisms driving the dynamics of the external compression ramp flow and the cowl SBLI in a Mach $3$ intake. Boundary layer transition over the external ramp is first analysed through a global linear analysis, and the linear estimates are further validated through direct numerical simulations. The separation bubble over the ramp harbours three-dimensional stationary instabilities that induce transition, under the influence of secondary instabilities driven by the shear layer modes of the bubble. The interaction of the resulting turbulized boundary layer with the cowl shock at the ramp–isolator junction and its control through geometrical modification constitutes the second part of the study. We tested a faceted (baseline) and a notched (modified) junction design to evaluate its impact on the low-, mid- and high-frequency scales generated at the cowl SBLI region. In relation to the baseline case, the notched geometry effectively locks the separation point of the bubble, thus attenuating the upstream low-frequency breathing motion. The notch also energizes the midfrequency content through vortex shedding in a well-developed shear layer, which persists into the isolator, thus assisting in an efficient compression process through cross-stream mixing of near-wall flow. The isolator boundary layer in the notched design exhibits relatively lower static pressures and higher velocity fluctuations, which are conducive to improving the flow stability, unstart margin and efficiency of high-speed propulsion systems.

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%