Visualization of unsteady shock oscillations in the High-enthalpy flow field around double cones

Jagadeesh, G.; Hashimoto, Tokitada; Naitou, Kazuyuki; Sun, Mingyu; Takayama, K.

doi:10.1007/bf03181624

Cited by 6 publications

(2 citation statements)

References 9 publications

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“…The phenomenon of flow unsteadiness is typically observed ahead of a wide range of axisymmetric forebodies, particularly when operating at supersonic and hypersonic velocities [1,2]. Various configurations, including mixed compression inlets [3,4], double cones [5,6], forward-facing cavities [7], axially positioned cavities [8], wall protrusions [9], and spiked/aerodisk forebodies [10][11][12], have been identified as significant sources of flow unsteadiness. This unsteadiness spans a broad spectrum of flow Reynolds numbers, which affects laminar and turbulent flow states [13][14][15].…”

Section: Introductionmentioning

confidence: 99%

Experimental Investigation of the Shock-Related Unsteadiness around a Spiked-Blunt Body Based on a Novel DMD Energy Sorting Criterion

Wang,

Xu,

Qin

et al. 2024

Aerospace

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In this study, we propose a novel dynamic mode decomposition (DMD) energy sorting criterion that works in conjunction with the conventional DMD amplitude-frequency sorting criterion on the high-dimensional schlieren dataset of the unsteady flow of a spiked-blunt body at Ma = 2.2. The study commences by conducting a comparative analysis of the eigenvalues, temporal coefficients, and spatial structures derived from the three sorting criteria. Then, the proper orthogonal decomposition (POD) and dynamic pressure signals are utilised as supplementary resources to explore their effectiveness in capturing spectral characteristics and spatial structures. The study concludes by summarising the characteristics and potential applications of DMD associated with each sorting criterion, as well as revealing the predominant flow features of the unsteady flow field around the spiked-blunt body at supersonic speeds. Results indicate that DMD using the energy sorting criterion outperforms the amplitude and frequency sorting criteria in identifying the primary structures of unsteady pulsations in the flow field, which proves its superiority in handling an experimental dataset of unsteady flow fields. Moreover, the unsteady pulsations in the flow field around the spiked-blunt body under supersonic inflow conditions are observed to exhibit multi-frequency coupling, with the primary frequency of 3.3 kHz originating from the periodic motion of the aftershock.

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Section: Introductionmentioning

confidence: 99%

Experimental Investigation of the Shock-Related Unsteadiness around a Spiked-Blunt Body Based on a Novel DMD Energy Sorting Criterion

Wang,

Xu,

Qin

et al. 2024

Aerospace

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“…The results of using CFI -Interferometry for investigation of flow separation around double cone are presented in [10]. The works [8,9] contained brief remarks about the use of CFI -Interferometry for investigation of jets.…”

Section: Introductionmentioning

confidence: 99%

Light refraction modeling for computational schlieren imaging in symmetrical flows

Ершов

Babichev

2007

Optics and Photonics for Information Processing

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A new approach is proposed for the calculation of refraction vector as a gradient of the phase shift when testing symmetrical flow with a parallel beam of light. It is assumed that the flow can be characterized by axial, conical or central symmetry. This is observed, for example, at supersonic flows around bodies of revolution. The density field between the bow shock wave and the body can be either calculated from the physics models or determined from the optical testing. The refraction vector modeling is based on polynomial representation of the radial density distributions. The confirmation of such representation is done by analysis of numerical data for various regimes of supersonic flows around bodies of revolution (sharp-tipped and blunt cones, spheres, bodies with ogive nose). Analytical formulas were obtained for refraction vector calculation in axial, conical and central symmetrical flows. For density field around a sphere in a supersonic flow at Mach number M=4, which was calculated from a physics model, refraction vector components were calculated for three different models. In the first model it is assumed that the phase change is taken place only on the bow shock wave. The second model uses a linear polynomial representation of the radial distributions based on density values calculated for the shock wave, symmetry axis and body surface. In the third model we used interpolation of the density values calculated in discrete points and least square method for polynomial representation. Results of the refraction vector calculations are illustrated by a set of graphics. The obtained formulas will be used further for the flow study using computational flow schlieren imaging technology. A recommendation is given on application of the formulas for this purpose.Keywords: light refraction vector, density field modeling, computational flow schlieren imaging.

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Surface pressure and heat transfer measurements in the unsteady separated hypersonic flow field over double cones

et al. 2005

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Visualization of unsteady shock oscillations in the High-enthalpy flow field around double cones

Cited by 6 publications

References 9 publications

Experimental Investigation of the Shock-Related Unsteadiness around a Spiked-Blunt Body Based on a Novel DMD Energy Sorting Criterion

Experimental Investigation of the Shock-Related Unsteadiness around a Spiked-Blunt Body Based on a Novel DMD Energy Sorting Criterion

Light refraction modeling for computational schlieren imaging in symmetrical flows

Surface pressure and heat transfer measurements in the unsteady separated hypersonic flow field over double cones

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