Boundary-Layer Instability Measurements in a Mach-6 Quiet Tunnel

Berridge, Dennis C.; Ward, Christopher A.; Luersen, Ryan P. K.; Chou, Amanda; Abney, Andrew; Schneider, Steven P.

doi:10.2514/6.2012-3147

Cited by 11 publications

(3 citation statements)

References 32 publications

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“…Models of the optimal design were built and tested in the Boeing/AFOSR Mach-6 Quiet Tunnel (BAM6QT) at Purdue University. In the BAM6QT, Berridge et al [180,181] and Ward et al [172] used temperature-sensitive paint to detect the surface heat ŕux. As shown in őgure streaks', were observed under quiet conditions.…”

Section: Flows Over Flared Conesmentioning

confidence: 99%

“…Ward et al [172] attributed the formation of these elongated structures to the interaction of Görtler vortices with the second Mack mode. Berridge et al [181] and Ward et al [172] tried to control these perturbations by roughness dots located upstream of the painted surface. Although good agreement was found between the computed and the measured wall-pressure spectrum, the dots were not able to control the growth of the streaky structures.…”

Section: Flows Over Flared Conesmentioning

confidence: 99%

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Görtler Instability and Transition in Compressible Flows

Xu,

Ricco,

Duan

2024

AIAA Journal

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We present a discussion on theoretical, experimental, and computational research studies on Görtler instability and the related transition to turbulence occurring in compressible boundary layers over concave surfaces. We first examine the theoretical results on primary and secondary instabilities, emphasizing the role of receptivity, the mechanism by which external agents, such as freestream fluctuations or wall roughness, act on a boundary layer to trigger Görtler vortices. We review experimental findings obtained from measurements in supersonic and hypersonic wind tunnels and discuss studies employing numerical methods, focusing on the direct numerical simulation approach. The research in these two last sections is surveyed according to the geometrical configuration, from simple concave walls to more complex surfaces of hypersonic vehicles. The experimental investigations have been successful in the visualizations of Görtler vortices, in the measurement of the wall-heat transfer in the transitional region, and in the computation of the Görtler-vortex growth rates, although detailed boundary-layer velocity measurements are still missing. Direct numerical simulations have confirmed instability results emerging from stability theories and revealed nonlinear interactions between Görtler vortices and other disturbances. The established initial-boundary-value receptivity theory can certainly benefit from more advanced experimental measurements, and receptivity results should be used in combination with direct numerical simulations. A major conclusion of our review is therefore that the understanding of Görtler vortices should be pursued by a combined methodology including theoretical analysis based on the receptivity formalism, direct numerical simulation, and experiments. Highly desirable outcomes of such endeavor are the prediction of the location and extension of the transition region, and a model for the transition process. We finally highlight further prospects and challenges on fundamental and applied research on Görtler instability and transition in compressible flows.

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Section: Flows Over Flared Conesmentioning

confidence: 99%

Section: Flows Over Flared Conesmentioning

confidence: 99%

Görtler Instability and Transition in Compressible Flows

Xu,

Ricco,

Duan

2024

AIAA Journal

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“…Recently, many researchers attempted to perform instability experiment with precision instruments [8] in "quiet" wind tunnel [9]. But comparing with the conventional wind tunnels, the size of "quite" wind tunnel is small and it also cannot simulate the conditions of flight test (such as the limitation of Reynolds number).…”

Section: Introductionmentioning

confidence: 99%

Extraction and analysis of the second mode instability wave based on singular-value decomposition and empirical mode decomposition

Xie,

2016

46th AIAA Fluid Dynamics Conference

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Hypersonic stability experiment was performed at FD-07 wind tunnel to research the boundary layer transition mechanism. A new analysis method based on singular-value decomposition (SVD) and empirical mode decomposition (EMD) was firstly implemented to extract the second mode instability wave from pressure fluctuation signal. Subsequently, the modulation characteristics of the second mode instability wave were analyzed by the complex digital demodulation technique. The results indicated that the second mode instability interacted with low frequency signals during hypersonic boundary layer transition, and the phase modulation was the most effective interaction mechanism.

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Investigation of the second-mode instability at Mach 14 using calibrated schlieren

Kennedy

Laurence

Smith³

et al. 2018

J. Fluid Mech.

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Second-mode wave growth within the hypersonic boundary layer of a slender cone is investigated experimentally using high-speed schlieren visualizations. Experiments were performed in AEDC Tunnel 9 over a range of unit Reynolds number conditions at a Mach number of approximately 14. A thin lens with a known density profile placed within the field of view enables calibration of the schlieren set-up, and the relatively high camera frame rates employed allow for the reconstruction of time-resolved pixel intensities at discrete streamwise locations. The calibration in conjunction with the reconstructed signals enables integrated spatial amplification rates ($N$ factors) to be calculated for each unit Reynolds number condition and compared to $N$ factors computed from both pressure transducer measurements and linear parabolized stability equation (PSE) solutions. Good agreement is observed between $N$ factors computed from the schlieren measurements and those computed from the PSE solutions for the most-amplified second-mode frequencies. The streamwise development of $N$ factors calculated from the schlieren measurements compares favourably to that calculated from the pressure measurements with slight variations in the $N$ factor magnitudes calculated for harmonic frequencies. Finally, a bispectral analysis is carried out to identify nonlinear phase-coupled quadratic interactions present within the boundary layer. Multiple interactions are identified and revealed to be associated with the growth of disturbances at higher harmonic frequencies.

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Boundary-Layer Instability Measurements in a Mach-6 Quiet Tunnel

Cited by 11 publications

References 32 publications

Görtler Instability and Transition in Compressible Flows

Görtler Instability and Transition in Compressible Flows

Extraction and analysis of the second mode instability wave based on singular-value decomposition and empirical mode decomposition

Investigation of the second-mode instability at Mach 14 using calibrated schlieren

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