Single-Camera Three-Dimensional Velocity Measurement of a Fin-Generated Shock-Wave/Boundary-Layer Interaction

Jones, Cassandra; Bolton, Johnathan T.; Clifford, Christopher J.; Thurow, Brian S.; Arora, Nishul; Alvi, Farrukh S.

doi:10.2514/1.j059184

Cited by 17 publications

(5 citation statements)

References 17 publications

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“…These parameters are chosen to facilitate comparisons, documented in previous work, with concurrent or archival experiments, depending on availability. Specifically, impinging shock simulations [3] were performed in coordination with experiments by Webb et al [84], swept-compression-ramp interactions [2,7] with experiments by Vanstone et al [81,82], Vanstone and Clemens [80], and sharp-fin interactions [4,7] with experiments by Arora et al [11], Baldwin et al [15], Mears et al [49], Arora et al [12], Mears et al [50], Jones et al [42]. Since recent double-fin interactions are not available, these are performed based on conditions of archival experiments by Garrison et al [36], Garrison and Settles [35] and archival RANS calculations by Gaitonde and Shang [27].…”

Section: Stbli Configurationsmentioning

confidence: 99%

“…Some previous results from these campaigns have been described in a variety of forms, including experimental measurements of the swept-compression-ramp (SCR) [80][81][82] and sharp-fin (SF) [11,12,15,42,49,50] interactions, along with high-fidelity large-eddy simulations [2,[4][5][6][7] of both configurations. The double-fin flowfield fosters a better understanding of the separation structure-unsteadiness connection, since it combines elements of swept 3-D interactions with those of 2-D interactions-the symmetry plane, for example, shows the influence of both-and thus aids in the establishment of a more comprehensive perspective.…”

Section: Introductionmentioning

confidence: 99%

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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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Section: Stbli Configurationsmentioning

confidence: 99%

Section: Introductionmentioning

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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“…CC BY 3.0. (C) Supersonic swept-fin [43] and (D) Leading-edge vortex dynamic about a rotating frame-of-reference [45].…”

Section: Principles and Hardware Of Lf Imagingmentioning

confidence: 99%

“…'Plenoptic-PIV' forms the core of LF flow diagnostics with successful applications in the studies of small marine animals [38] (figures 5(A) and 6(A)), compressor linear cascade [39] (figures 5(B) and 6(B)), birds and maneuvering wings [40], riverbed boundary-layer [41], shock-boundary layer interactions [42,43] (figures 5(C) and 6(C)), thin liquid film [44], rotating helicopter blade [45] (figures 5(D) and 6(D)), transcatheter heart valves [46] and numerous others. In figures 5 and 6's examples, constraints on optical access and depth of volume would have made a multi-camera system very challenging to implement.…”

Section: Application To Flow Velocimetrymentioning

confidence: 99%

Perspective on the development and application of light-field cameras in flow diagnostics

Tan

Thurow

2021

Meas. Sci. Technol.

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Multi-camera flow diagnostics have made large gains in recent years in the field of three-dimensional and multi-physics measurements. However, cost, complexity and optical access pose challenges that place multi-camera techniques out of reach for many labs. In that context, light-field (LF) imaging represents an alternative approach that can potentially alleviate some of these challenges. LF flow diagnostics is a branch of measurement techniques introduced within the last decade that are based on a plenoptic camera's unique ability to capture three-dimensional and multi-spectral data via a single objective lens and image sensor-albeit at reduced lateral resolutions and depth-to-lateral uncertainty ratios of 3-10 due to limited parallax angle. Thus far, LF flow diagnostics have successfully achieved significant camera-reduction alongside other performance improvements in 3D flow velocimetry, 3D particle tracking, 3D scalar-field tomography, micro-fluidic velocimetry and multi-spectral imaging, as well as early demonstrations of single-camera multi-physics measurements for applications such as 3D fluid-structure interactions. Here, we discuss the state of development in LF flow diagnostics, highlight on-going challenges, and project potential advancements in the near future.

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“…In recent studies, various approaches [9][10][11][12] have been explored to understand and control shock wave-boundary layer interactions (SBLIs) and their impact on aerodynamic performance. One such study conducted by Genç et al [13] focuses on passive flow control methods for UAVs and MAVs operating at low Reynolds numbers, aiming to address issues related to SWBLI.…”

Section: Introductionmentioning

confidence: 99%

Effects of Perforated Plates on Shock Structure Alteration for NACA0012 Airfoils

Gall,

Dumitrescu,

Drăgan

et al. 2024

Inventions

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This research investigated a passive flow control technique to mitigate the adverse effects of shock wave–boundary layer interaction on a NACA 0012 airfoil. A perforated plate with a strategically positioned cavity beneath the shock wave anchoring spot was employed. Airfoils with perforated plates of varying orifice sizes (ranging from 0.5 to 1.2 mm) were constructed using various manufacturing techniques. Experimental analysis utilized an “Eiffel”-type open wind tunnel and a Z-type Schlieren system for flow visualization, along with static pressure measurements obtained from the bottom wall. Empirical observations were compared with steady 3D density-based numerical simulations conducted in Ansys FLUENT for comprehensive analysis and validation. The implementation of the perforated plate induced a significant alteration in shock structure, transforming it from a strong normal shock wave into a large lambda-type shock. The passive control case exhibited a 0.2% improvement in total pressure loss and attributed to the perforated plate’s capability to diminish the intensity of the shock wave anchored above. Significant fluctuations in shear stress were introduced by the perforated plate, with lower stress observed in the plate area due to flow detachment from cavity blowing. Balancing shock and viscous losses proved crucial for achieving a favorable outcome with this passive flow control method.

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Single-Camera Three-Dimensional Velocity Measurement of a Fin-Generated Shock-Wave/Boundary-Layer Interaction

Cited by 17 publications

References 17 publications

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

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

Perspective on the development and application of light-field cameras in flow diagnostics

Effects of Perforated Plates on Shock Structure Alteration for NACA0012 Airfoils

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