Zones of Influence and Shock Motion in a Shock/Boundary-Layer Interaction

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

doi:10.2514/1.j051516

Cited by 71 publications

(8 citation statements)

References 34 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Besides the corrugation of the reattachment shock, Mach wave radiation induces disturbances along the reflected shock above the shock-intersection location. Similar results have been found by Agostini et al (2012) through cross-correlation maps between the pressure field and time series of the streamwise location of the reflected shock for their LES studies of incipient, mildly and fully separated SWBLI at Ma = 2.3 and Re δ0 ≈ 60 ⋅ 10 3 (see figure 8 in the respective publication). The supplementary online material further highlights that the modes φ 3 and φ 4 primarily influence the rear part of the separation bubble starting from the bubble apex.…”

Section: = Uσvsupporting

confidence: 70%

“…Touber & Sandham (2009) were probably among the first to publish a successful comparison between their long-time (10 4 δ 0 U 0 ) narrow-domain LES results and experimental data with respect to the unsteady shock motion. Further LES studies for impinging SWBLI with a focus on low-frequency aspects of the interaction have been published thereafter (Pirozzoli et al 2010;Hadjadj 2012;Agostini et al 2012;Aubard et al 2013;Morgan et al 2013;Pasquariello et al 2014;Nichols et al 2016). All of these studies, however, predominantly focused on weak interactions (with respect to the absence of a distinct pressure plateau within the separated flow) and/or low Reynolds numbers being typically below Re δ0 ≈ 60 ⋅ 10 3 .…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Unsteady effects of strong shock-wave/boundary-layer interaction at high Reynolds number

2017

View full text Add to dashboard Cite

We analyse the low-frequency dynamics of a high-Reynolds-number impinging shockwave/turbulent boundary-layer interaction (SWBLI) with strong mean-flow separation. The flow configuration for our grid-converged large-eddy simulations (LES) reproduces recent experiments for the interaction of a Mach 3 turbulent boundary layer with an impinging shock that nominally deflects the incoming flow by 19.6○ . The Reynolds number based on the incoming boundary layer thickness of Re δ0 ≈ 203 ⋅ 10 3 is considerably higher than in previous LES studies. The very long integration time of 3805 δ 0 U 0 allows for an accurate analysis of low-frequency unsteady effects. Experimental wallpressure measurements are in good agreement with the LES data. Both datasets exhibit the distinct plateau within the separated-flow region of a strong SWBLI. The filtered three-dimensional flow field shows clear evidence of counter-rotating streamwise vortices originating in the proximity of the bubble apex. Contrary to previous numerical results on compression ramp configurations, these Görtler-like vortices are not fixed at a specific spanwise position, but rather undergo a slow motion coupled to the separationbubble dynamics. Consistent with experimental data, power spectral densities (PSD) of wall-pressure probes exhibit a broadband and very energetic low-frequency component associated with the separation-shock unsteadiness. Sparsity-promoting dynamic mode decompositions (SPDMD) for both spanwise-averaged data and wall-plane snapshots yield a classical and well-known low-frequency breathing mode of the separation bubble, as well as a medium-frequency shedding mode responsible for reflected and reattachment shock corrugation. SPDMD of the two-dimensional skin-friction coefficient further identify streamwise streaks at low frequencies that cause large-scale flapping of the reattachment line. The PSD and SPDMD results of our impinging SWBLI support the theory that an intrinsic mechanism of the interaction zone is responsible for the lowfrequency unsteadiness, in which Görtler-like vortices might be seen as a continuous (coherent) forcing for strong SWBLI.

show abstract

Section: = Uσvsupporting

confidence: 70%

Section: Introductionmentioning

confidence: 99%

Unsteady effects of strong shock-wave/boundary-layer interaction at high Reynolds number

2017

View full text Add to dashboard Cite

show abstract

“…Due to the inflection point in the velocity profiles, the shear layer is unstable and large-scale vortical structures are formed, which have been observed in a number of STBLI studies (e.g. Dupont et al 2008;Humble et al 2009;Agostini et al 2012).…”

mentioning

confidence: 91%

Low-frequency dynamics in a shock-induced separated flow

et al. 2016

View full text Add to dashboard Cite

The low-frequency unsteadiness in the direct numerical simulation of a Mach 2.9 shock wave/turbulent boundary layer interaction with mean flow separation is analysed using dynamic mode decomposition (DMD). The analysis is applied both to threedimensional and spanwise-averaged snapshots of the flow. The observed low-frequency DMD modes all share a common structure, characterized by perturbations along the shock, together with streamwise-elongated regions of low and high momentum that originate at the shock foot and extend into the downstream flow. A linear superposition of these modes, with dynamics governed by their corresponding DMD eigenvalues, accurately captures the unsteadiness of the shock. In addition, DMD analysis shows that the downstream regions of low and high momentum are unsteady and that their unsteadiness is linked to the unsteadiness of the shock. The observed flow structures in the downstream flow are reminiscent of Görtler-like vortices that are present in this type of flow due to an underlying centrifugal instability, suggesting a possible physical mechanism for the low-frequency unsteadiness in shock wave/turbulent boundary layer interactions.

show abstract

“…This trend is also found in the literature. 14 The frequencies discovered within the interaction provided a starting point for the forcing experiments. By providing information regarding the natural instabilities within the interaction, they suggest instabilities that might be exploited in order to control the flow.…”

Section: Time-resolved Pressure Measurementsmentioning

confidence: 99%

Supersonic Inlet Flow Control Using Localized Arc Filament Plasma Actuators

Samimy¹,

Webb²,

Clifford³

2011

View full text Add to dashboard Cite

Public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing this collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing this burden to Department of Defense, Washington Headquarters Services, Directorate for Information Unlimited.Shock Wave/Boundary Layer Interactions (SWBLIs) occur in many applications of interest to the U.S. Air Force and could pose significant problems depending on the specific application. This study has undertaken to investigate the use of ). This frequency is similar to that at which the reflected shock oscillates in unforced SWBLIs. Therefore, LAFPAs are believed to manipulate the natural instability associated with the reflected shock oscillation. The success of the preliminary experiments motivated the design of a new, larger, more flexible facility that utilize a Variable Angle Wedge (VAW) (rather than a compression ramp) to generate the impinging shock wave for SWBLI. This facility is capable of easily generating a wide range of SWBLI strengths, but was found to be a poor environment for testing the LAFPAs control authority due to its inability to modify the LAFPA location. The necessary modifications to add this capability to the facility have been performed. This research is currently continuing with the focus on investigating the actuation authority and mechanism at various SWBLI strengths as well as on the optimization of the control authority.

show abstract

Zones of Influence and Shock Motion in a Shock/Boundary-Layer Interaction

Cited by 71 publications

References 34 publications

Unsteady effects of strong shock-wave/boundary-layer interaction at high Reynolds number

Unsteady effects of strong shock-wave/boundary-layer interaction at high Reynolds number

Low-frequency dynamics in a shock-induced separated flow

Supersonic Inlet Flow Control Using Localized Arc Filament Plasma Actuators

Contact Info

Product

Resources

About