Streamwise vortices in reattaching high-speed flows - A suggested approach

Ginoux, Jean J.

doi:10.2514/3.6271

Cited by 63 publications

(39 citation statements)

References 2 publications

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“…Probably the first who observed and documented the streamwise vortices in reattaching supersonic turbulent flow was Ginoux (1971). Experiments on backward facing steps and axisymmetric hollow cylinder flare showed a striation pattern at the surface with a wavelength of about two to three boundary layer thicknesses.…”

Section: Flow Physics Of Swtblimentioning

confidence: 99%

Large-eddy simulation of shock-wave/turbulent-boundary-layer interaction

2006

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Well-resolved large-eddy simulations (LES) are performed in order to investigate flow phenomena and turbulence structure of the boundary layer along a supersonic compression ramp. The numerical simulations directly reproduce an available experimental result. The compression ramp has a deflection angle of $\beta\,{=}\,25^\circ$. The mean free-stream Mach number is $M_\infty\,{=}\,2.95$. The Reynolds number based on the incoming boundary-layer thickness is $Re_{\delta_0}\,{=}\,63\,560$ in accordance with the reference experiment. These simulations overcome deficiencies of earlier direct numerical simulations (DNS) and LES in terms of ramp-deflection angle, Reynolds number and spanwise size of the computational domain which is required for capturing the essential flow phenomena. The filtered conservation equations for mass, momentum and energy are solved with a high-order finite-difference scheme. The effect of subgrid scales is modelled by the approximate deconvolution model. About $18.5\,{\times}\,10^6$ grid points are used for discretizing the computational domain. To obtain mean flow and turbulence structure the flow is sampled 1272 times over 703 characteristic time scales of the incoming boundary layer. Statistical data are computed from these samples. An analysis of the data shows good agreement with the experiment in terms of mean quantities such as shock position, separation and reattachment location, skin-friction and surface-pressure distributions, and turbulence structure. The computational data confirm theoretical and experimental results on fluctuation amplification across the interaction region. In the wake of the main shock a shedding of shocklets is observed. The temporal behaviour of the coupled shock–separation system agrees well with experimental data. Unlike previous DNS the present simulation data provide indications of a large-scale shock motion. Also, evidence for the existence of three-dimensional large-scale streamwise structures, commonly referred to as Görtler-like vortices, is found.

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Section: Flow Physics Of Swtblimentioning

confidence: 99%

Large-eddy simulation of shock-wave/turbulent-boundary-layer interaction

2006

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“…Ginoux (1971) observed the presence of Goertler vortices in the reattaching flow downstream of a descendent step at a Mach number of 5.3. More recently E1 Hady and Verma (1983), Spall and Malik (1989), Jallade (1990), Aymer de la Chevalerie et al (1991) published numerical results about the compressible Goertler problem, including the pressure gradient as well as wall temperature influence.…”

Section: Introduction and Theoretical Remarksmentioning

confidence: 99%

Goertler instability of a hypersonic boundary layer

Luca

Cardone

Chevalerie

et al. 1993

Experiments in Fluids

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The Goertler instability of a hypersonic boundary layer A and its influence on the wall heat transfer are experimentally ana-2 lyzed. Measurements, made in a wind tunnel by means of a p computerized infrared (IR) imaging system, refer to the flow over 51 two-dimensional concave walls. Wall temperature maps (that are a interpreted as surface flow visualizations) and spanwise heat transfer 6-fluctuations are presented. Measured vortices wavelengths are corre-0 lated to non-dimensional parameters and compared with numerical 0' predictions from the literature.

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“…Similarities with the compression corner results of Loginov et al (2006) discussed previously suggest that a similar centrifugal instability plays a role for the current SWBLI, which would explain the increased spanwise Reynolds stress found in figure 8(c). Furthermore, the PME centred at the bubble apex, the dividing streamline and the downstream recompression correspond to a two-dimensional supersonic backward-facing step flow, for which streamwise vortices have been found experimentally in laminar, transitional and turbulent flows over a large range of Mach numbers (Ginoux 1971).…”

Section: Instantaneous and Mean Flow Organisationmentioning

confidence: 99%

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

2017

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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.

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Streamwise vortices in reattaching high-speed flows - A suggested approach

Abstract: TECHNICAL NOTES 759The solution of Eq. (6) for a given ml/M is denoted as k D . Table 1 presents values of k D for given ml/M, and Fig. 1 plots 0"(0)/(7(0)cj for a wide range of k.

Cited by 63 publications

References 2 publications

Large-eddy simulation of shock-wave/turbulent-boundary-layer interaction

Large-eddy simulation of shock-wave/turbulent-boundary-layer interaction

Goertler instability of a hypersonic boundary layer

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

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