High-Speed Schlieren Imaging of Cylinder-Induced Hypersonic-Shock-Wave–Boundary-Layer Interactions

Leidy, Andrew; Neel, Ian T.; Tichenor, Nathan R.; Bowersox, Rodney D. W.

doi:10.2514/1.j059193

Cited by 13 publications

(3 citation statements)

References 38 publications

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“…The contrasting flow features between shock pulsations and oscillations were also studied by a comparison of the Fourier spectra obtained from time-resolved schlieren data. Analysis of the spectral content of temporal fluctuations in the local spatial density gradient (which is captured by schlieren) can give useful insights into the frequencies associated with flow features of interest (Leidy et al 2020). Figure 7 presents maps of power spectral density (Φ) of image intensity fluctuations for the pulsation and oscillation cases shown in figures 5 and 6, respectively.…”

Section: Spectral Analysismentioning

confidence: 99%

Large- and small-amplitude shock-wave oscillations over axisymmetric bodies in high-speed flow

Sasidharan

Subrahmanyam

2021

J. Fluid Mech.

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Section: Spectral Analysismentioning

confidence: 99%

Large- and small-amplitude shock-wave oscillations over axisymmetric bodies in high-speed flow

Sasidharan

Subrahmanyam

2021

J. Fluid Mech.

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“…Shock wave boundary layer interaction (SWBLI) patterns produced by a circular cylinder installed on the wall of a supersonic duct have been widely studied, including the associated flow/BL structures [1][2][3], shock structures [4], and pressure distributions [5]. Experimental and numerical techniques have been used to explore the flow field around cylinders normal to the wall [6] and parallel to the wall [7].…”

Section: Introductionmentioning

confidence: 99%

Flow Structure behind Spanwise Pin Array in Supersonic Flow

Lax,

Elliott,

Gordeyev

et al. 2024

Aerospace

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This work focused on the experimental characterization of a complex flow structure behind a cross-flow array of cylindrical pins installed on the wall of a supersonic duct. This geometry simulates several common gas dynamic configurations, such as a supersonic mixer, a turbulence-generating grid, or, to some extent, a grid fin. In this work, the instrumentation employed is essentially non-intrusive, including spanwise integrating techniques such as (1) fast schlieren visualization and (2) Shack–Hartmann wavefront sensors; and planar techniques, namely (3) acetone Mie scattering and (4) acetone planar laser-induced fluorescence. An analysis of the data acquired by these complementary methods allowed the reconstruction of a three-dimensional portrait of supersonic flow interactions with a discrete pin array, including the shock wave structure, forefront separation zone, shock-induced separation zone, shear layer, and the mixing zone behind the pins. The main objective of this activity was to use various visualization techniques to acquire essential details of a complex compressible flow in a wide range of temporal–spatial scales. Particularly, a fine structure in the supersonic shear layer generated by the pin tips was captured by a Mie scattering technique. Based on the available publications, such structures have not been previously identified or discussed. Another potential outcome of this work is that the details revealed could be utilized for adequate code validation in numerical simulations.

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“…Mubarak and Tide (2018a) further investigated and found that the shock cell count and magnitude of the included shock angle of double parabolic nozzle is less when compared with the other two nozzle configurations. Leidy et al (2020) used high-speed Schlieren imaging for visualizing cylinder induced hypersonic shock wave boundary layer interaction that helps to capture the true form of upstream influence of shock.…”

Section: Introductionmentioning

confidence: 99%

Schlieren imaging investigation on azimuthally varying shock net from four-lobed corrugated nozzle

K.G.

Paul

P.S.

et al. 2022

AEAT

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Purpose The purpose of this paper is to conduct an experimental investigation on the shock cell structure of jets emanating from a four-lobed corrugated nozzle using Schlieren imaging technique. Design/methodology/approach The Schlieren images were captured for seven different nozzle pressure ratios (NPR = 2, 3, 4, 5, 6, 7 and 8) and compared with the shock cell structure of a round nozzle with an identical exit area. The variation in the length of the shock cell, width of boundary interaction between adjacent shock cells, maximum width of first shock cell, Mach disk position and diameter for different NPR was measured from the Schlieren images and analysed. Findings A three-layer shock net observed in the jet emanating from the four-lobed corrugated nozzle is a novel concept in the field of under-expanded jet flows. A shock net represents interconnected layers of shock cells developed because of the interaction between the core and peripheral shock waves in a jet emanating from a corrugated lobed nozzle. Also, the pattern of shock net is different while taking Schlieren images across the groove and lobe sections. Thus, the shock net emerging from a corrugated lobed nozzle varies azimuthally and primarily depends on the nozzle exit cross section. The length of the shock cell, width of boundary interaction between adjacent shock cells, maximum width of first cell, Mach disk position and diameter were found to exhibit increasing trend with NPR. Originality/value A novel concept of interconnected layers of shock waves defined as “shock net” developed from a single jet emanating from a four-lobed corrugated nozzle was observed.

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High-Speed Schlieren Imaging of Cylinder-Induced Hypersonic-Shock-Wave–Boundary-Layer Interactions

Cited by 13 publications

References 38 publications

Large- and small-amplitude shock-wave oscillations over axisymmetric bodies in high-speed flow

Large- and small-amplitude shock-wave oscillations over axisymmetric bodies in high-speed flow

Flow Structure behind Spanwise Pin Array in Supersonic Flow

Schlieren imaging investigation on azimuthally varying shock net from four-lobed corrugated nozzle

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