Effects of Reynolds Number on Swept Shock-Wave/Boundary-Layer Interactions

Baldwin, Andrew; Mears, Lee; Kumar, Rajan; Alvi, Farrukh S.

doi:10.2514/1.j060293

Cited by 14 publications

(5 citation statements)

References 32 publications

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“…The distribution of Reynolds stresses and turbulent kinetic energy have not been probed in quite as much detail as for 2D interactions; nonetheless, some understanding of these quantities may be found in Adler & Gaitonde (2019). Baldwin et al (2021) explored the effect of scale by obtaining results in different facilities for interactions at similar Mach numbers but different Reynolds numbers; the results are similar in form, and a method of mapping between different interaction sizes has been proposed.…”

Section: Asymptotic Swept Interactions: Flow Structurementioning

confidence: 99%

Dynamics of Three-Dimensional Shock-Wave/Boundary-Layer Interactions

Gaitonde

Adler

2023

Annu. Rev. Fluid Mech.

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Advances in measuring and understanding separated, nominally two-dimensional (2D) shock-wave/turbulent-boundary-layer interactions (STBLI) have triggered recent campaigns focused on three-dimensional (3D) STBLI, which display far greater configuration diversity. Nonetheless, unifying properties emerge for semi-infinite interactions, taking the form of conical asymptotic behavior where shock-generator specifics become insignificant. The contrast between 2D and 3D separation is substantial; the skewed vortical structure of 3D STBLI reflects the essentially 2D influence of the boundary layer on the 3D character of the swept shock. As with 2D STBLI, conical interactions engender prominent spectral content below that of the turbulent boundary layer. However, the uniform separation length scale, which is crucial to normalizing the lowest-frequency dynamics in 2D STBLI, is absent. Comparatively, the spectra of 3D STBLI are more representative of the mid-frequency, convective, shear-layer dynamics in 2D, while phenomena associated with 2D separation-shock breathing are muted. Asymptotic behavior breaks down in many regions important to 3D-STBLI dynamics, occurring in a configuration-dependent manner. Aspects of inceptive regions near shock generators and symmetry planes are reviewed. Focused efforts toward 3D modal and nonmodal analyses, moving-shock/boundary-layer interactions, fluid/structure interactions, and flow control are suggested as directions for future work. Expected final online publication date for the Annual Review of Fluid Mechanics, Volume 55 is January 2023. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

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Section: Asymptotic Swept Interactions: Flow Structurementioning

confidence: 99%

Dynamics of Three-Dimensional Shock-Wave/Boundary-Layer Interactions

Gaitonde

Adler

2023

Annu. Rev. Fluid Mech.

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“…The interaction length was found to scale with the displacement thickness of the upstream turbulent boundary layer. Furthermore, Baldwin et al [21] showed that compared to the shock generator angle and freestream Mach number, which determine the interaction strength, the Reynolds number is a secondary factor in governing the interaction. Additionally, the sensitivity of the flow to the Reynolds number was found to decrease for higher Reynolds numbers and stronger interactions.…”

Section: Overview Of Simulationsmentioning

confidence: 99%

“…Of the scarce amount of 3D SBLI research, the majority has primarily focused on sharp fins [19][20][21], swept compression ramps [22,23], and swept impinging oblique shock waves [6,24,25]. Some recent work by Zuo et al [26] considered the interaction of a conical shock wave with a flat plate boundary layer.…”

Section: Introductionmentioning

confidence: 99%

Numerical Investigation of Asymmetric Mach 2.5 Turbulent Shock Wave Boundary Layer Interaction

Groß

Slater

2023

Aerospace

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Supersonic shock wave boundary layer interactions are common to inlet flows of supersonic and hypersonic vehicles. This paper reports on wall-resolved implicit large-eddy simulations of a canonical Mach 2.5 turbulent shock wave boundary layer interaction experiment at the NASA Glenn Research Center. The boundary layer upstream of the interaction was nominally axisymmetric and two-dimensional. A conical centerbody with a 16 deg half-angle and a maximum radius of 0.147D of the test section diameter was employed to generate a conical shock wave, where D is the test section diameter. Asymmetric (swept) interactions were obtained by displacing the shock generator away from the test section centerline. The present simulation is for a shock generator displacement of D/6. Results from the asymmetric simulation are compared with results from an earlier simulation of a corresponding axisymmetric interaction. The experimental Reynolds number based on test section diameter was ReD=4×106. For the simulations, the Reynolds number was lowered to ReD=4×105 to keep the computational expense of the simulations within limits. Compared to the axisymmetric interaction, the streamwise extent of the separation varies considerably in the azimuthal direction for the asymmetric interaction. The separation is strongest at the azimuthal location that is closest to the shock generator. The streamwise extent of the separated flow regions is noticeably reduced and substantial crossflow is observed between the locations that are closest and farthest from the shock generator. A Fourier analysis of the unsteady flow data indicates low-frequency content for the separated region that is closest to the shock generator. Away from this region, with increasing sweep angle and cross-flow, the low-frequency content is diminished. A proper orthogonal decomposition captures spanwise coherent structures for the more two-dimensional parts of the interaction.

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“…1, the evidence for both 2-D [25] as well as simple, swept, 3-D interactions [7] suggests that the unsteadiness mechanisms have relatively similar behavior across a range of Mach and Reynolds numbers. Particularly, for 3-D interactions, a larger parameter space should be investigated moving forward to better quantify the degree of similarity with respect to these properties [14]. Employing proper length and velocity scales for normalization facilitates the comparison of spatio-temporal scales of different mechanisms associated with each interaction type across a range of flow parameters.…”

Section: Stbli Configurationsmentioning

confidence: 99%

Influence of separation structure on the dynamics of shock/turbulent-boundary-layer interactions

Adler

Gaitonde

2021

Theor. Comput. Fluid Dyn.

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Shock/turbulent-boundary-layer interactions (STBLIs) are ubiquitous in high-speed flight and propulsion applications. Experimental and computational investigations of swept, three-dimensional (3-D) interactions, which exhibit quasi-conical mean-flow symmetry in the limit of infinite span, have demonstrated key differences in unsteadiness from their analogous, two-dimensional (2-D), spanwise-homogeneous counterparts. For swept interactions, represented by the swept–fin-on-plate and swept–compression–ramp-on-plate configurations, differences associated with the separated shear layers may be traced to the intermixing of 2-D (spanwise independent) and 3-D (spanwise dependent) scaling laws for the separated mean flow. This results in a broader spectrum of unsteadiness that includes relatively lower frequencies associated with the separated shear layers in 3-D interactions. However, lower frequency ranges associated with the global “breathing” of strongly separated 2-D interactions are significantly less prominent in these simple, swept 3-D interactions. A logical extension of 3-D interaction complexity is the compound interaction formed by the merging of two simple interactions. The first objective of this work is therefore to analyze the more complex picture of the dynamics of such interactions, by considering as an exemplar, wall-resolved simulations of the double-fin-on-plate configuration. We show that in the region of interaction merging, new flow scales, changes in separation topology, and the emergence of lower-frequency phenomena are observed, whereas the dynamics of the interaction near the fin leading edges are similar to those of the simple, swept interactions. The second objective is to evolve a unified understanding of the dynamics of STBLIs associated with complex configurations relevant to actual propulsion systems, which involve the coupling between multiple shock systems and multiple flow separation and attachment events. For this, we revisit the salient aspects of scaling phenomena in a manner that aids in assimilating the double-fin flow with simpler swept interactions. The emphasis is on the influence of the underlying structure of the separated flow on the dynamics. The distinct features of the compound interactions manifest in a centerline symmetry pattern that replaces the quasi-conical symmetry of simple interactions. The primary separation displays topological closure to reveal new length scales, associated unsteadiness bands, and secondary flow separation.

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Effects of Reynolds Number on Swept Shock-Wave/Boundary-Layer Interactions

Cited by 14 publications

References 32 publications

Dynamics of Three-Dimensional Shock-Wave/Boundary-Layer Interactions

Dynamics of Three-Dimensional Shock-Wave/Boundary-Layer Interactions

Numerical Investigation of Asymmetric Mach 2.5 Turbulent Shock Wave Boundary Layer Interaction

Influence of separation structure on the dynamics of shock/turbulent-boundary-layer interactions

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