Unsteadiness in shock wave boundary layer interactions with separation

Dussauge, Jean‐Paul; Dupont, Pierre; Debiève, J. F.

doi:10.1016/j.ast.2005.09.006

Cited by 375 publications

(230 citation statements)

References 21 publications

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“…The imposed §ow de §ection angle is 9.5 • , corresponding to a well developed separation. The baseline interaction has been extensively documented in literature [5,7,8]. As can be observed, the boundary layer is ¦rst perturbed by the AJVG array, which is located at the source of the weak shock-expansion system located upstream of the interaction.…”

Section: General Description Of the Flowmentioning

confidence: 96%

Effect on a shock wave boundary layer interaction of air jet vortex generators

Souverein

Debiève

2012

Progress in Flight Physics

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The e¨ect of upstream injection by means of continuous Air Jet Vortex Generators (AJVGs) on a shock wave turbulent boundary layer interaction is experimentally investigated. The baseline interaction is of the impinging type, with a §ow de §ection angle of 9.5 • , a Mach number M e = 2.3, and a momentum thickness based Reynolds number of 5,000. Considered are the e¨ects of the AJVGs on the upstream boundary layer §ow topology and on the spatial and dynamical characteristics of the interaction. To this aim, Stereoscopic Particle Image Velocimetry has been employed, in addition to hot-wire anemometry (HWA) for the investigation of the dynamical characteristics of the re §ected shock. It is shown that the AJVGs signi¦cantly modify the three-dimensionality of the upstream boundary layer. Overall, the AJVGs cause a reduction of the separation bubble length and height. In addition, the energetic frequency range of the re §ected shock is increased by approximately 50%, which is in qualitative agreement with the smaller separation bubble size.

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Section: General Description Of the Flowmentioning

confidence: 96%

Effect on a shock wave boundary layer interaction of air jet vortex generators

Souverein

Debiève

2012

Progress in Flight Physics

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“…It is important to note that the spectra are smooth with no peaks or bumps such as the ones noticed in the experiments by Bourgoing and Reijasse. 9 This implies that the unsteadiness is not governed by any resonant interactions, but rather by random fluctuations.…”

Section: A Statistics Of Shock Motionmentioning

confidence: 99%

“…n n E E r − ≡ +1 (9) where the error function E is defined by Convergence was based on a set limit of r≤10 -10 .…”

Section: Tracking Of Shock Positionmentioning

confidence: 99%

“…Even though some experiments and analyses have shown that the shock motion can be influenced by turbulent fluctuations in the attached boundary layer upstream, 6,7,8 it would seem that in general, the primary excitation comes from fluctuation in the downstream separated flow. This is reflected in a comprehensive review of several experiments by Dussauge et al 9 In an investigation motivated by the occurrence of side loads in rocket nozzles, Bourgoing and Reijasse 10 studied unsteady shock behavior in a two-throated planar nozzle undergoing both symmetric and asymmetric separation. The presence of the second throat resulted in the reattachment of the recirculation regions downstream of the shock.…”

mentioning

confidence: 99%

“…Wall pressure spectra measured near the recirculation regions showed two spectral bumps. Dussauge 9 suggests that the lower and higher frequency bumps may be associated with the finite length of the larger and smaller recirculation zones respectively. This notion is supported by the relatively broadband wall pressure spectra obtained in the experiments at UC Irvine, in which the separation zones downstream of the main shock did not reattach.…”

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confidence: 99%

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Shock Motion and Flow Instabilities in Supersonic Nozzle Flow Separation

Johnson

Papamoschou

2008

38th Fluid Dynamics Conference and Exhibit

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This study evaluates the role of shock wave motion on the instability of the plume exiting an over-expanded, convergent-divergent nozzle. An array of wall pressure transducers was used to track the position of the shock in time, and a Pitot probe was used to obtain simultaneous measurement of the total pressure fluctuations at various points in the jet that emerges from the separation shock. Analysis of the shock motion revealed that the shock wave becomes more unstable as it becomes stronger, as evidenced by an increase in the range of motion and in the frequency of large-scale oscillations. For strong shocks, there is a substantial correlation between shock motion and total pressure fluctuation in the plume. Such correlation is absent for relatively weak shocks. The study indicates that shock motion affects the plume instability if the separation shock is very strong, and that other mechanisms govern the plume instability when the shock is relatively weak. Nomenclature A= cross sectional area

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