Hypersonic Stability and Transition Experiments on Blunt Cones and a Generic Scramjet Forebody

Schneider, Steven P.; Matsumura, Shin; Rufer, Shann J.; Skoch, Craig; Swanson, Erick

doi:10.2514/6.2003-1130

Cited by 11 publications

(9 citation statements)

References 40 publications

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“…This seems particularly likely because for reattaching shear layers above separation bubbles that can occur in compression corners vorticity from the leading edge is known to be a triggering mechanism. 13 Streamwise vortices are commonly observed in heattransfer rate measurements at reattachment; these are presumably generated by an unknown instability in the shear layer. 19,20 Detailed study of these streamwise vortices using infrared imaging showed that their location can be unambiguously connected to small flows in the leading edge.…”

Section: Flowfield Properties On a Generic Forebodymentioning

confidence: 99%

Streamwise Vortex Instability and Transition on the Hyper-2000 Scramjet Forebody

Matsumura

Schneider

Berry

2005

Journal of Spacecraft and Rockets

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Despite the closely coupled multidisciplinary design of hypersonic airbreathing vehicles, the boundary-layer transition mechanisms that are important on the forebody ahead of the scramjet inlet are not well understood. Transition induced by the growth of streamwise vortices on a scramjet forebody geometry is investigated. Characteristics of the separation zone near the first compression corner are visualized with oil-flow experiments. These experiments also reveal the presence of regularly spaced streamwise vortices on the compression ramp even in the absence of controlled disturbance generators. The growth and decay of these vortices are inferred from the heattransfer rates measured using temperature-sensitive paints. The streamwise vortices are enhanced in a controlled and repeatable manner by wrapping tapes around the leading edge. The vortices grow significantly on the second compression ramp and then decay, suggesting transition onset. The disturbance growth seems to show a systematic trend with unit Reynolds number, although this trend was not consistently seen for all cases. For some of the cases, the disturbances showed the largest growth when the roughness spacing was close to the vortex spacing seen in the oil-flow images. Nomenclature A = instability amplitude I = temperature-sensitive-paint luminescence intensity, counts k = thermal conductivity, W/m-K q = heat-transfer rate, W/cm 2 T = temperature, K T i = model initial temperature, K t = insulator thickness, mils x = model streamwise coordinate, in. x = model streamwise coordinate in the image plane, pixels y = model spanwise coordinate, in. y = model spanwise coordinate in the image plane, pixels

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Section: Flowfield Properties On a Generic Forebodymentioning

confidence: 99%

Streamwise Vortex Instability and Transition on the Hyper-2000 Scramjet Forebody

Matsumura

Schneider

Berry

2005

Journal of Spacecraft and Rockets

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“…It appears that the kink in the electroformed throat exacerbated a natural tendency to form an unstable separation bubble near the lip [19]. Separation bubbles on the bleed lip and associated fluctuations induced near the bleed lip were identified by Schneider et al [20] as the most likely cause of early transition. Taskinoglu et al [21,22] were the first to make a detailed computation of separation bubble structure and location.…”

Section: Computational Fluid Dynamics Simulations For the Redesign Ofmentioning

confidence: 96%

Quiet-Flow Ludwieg Tube for Hypersonic Transition Research

et al. 2008

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Nearly all hypersonic tunnels have turbulent nozzle-wall boundary layers that radiate acoustic noise, generating high freestream noise levels that are an order of magnitude above flight levels. A new Mach-6 quiet tunnel has been developed to provide quiet flow at high Reynolds number with low noise levels, comparable with flight. Laminar nozzle-wall boundary layers and the resulting quiet flow have now been achieved to high Reynolds numbers of 3:5 10 6 =ft (11 10 6 =m), after five years of shakedown. The Mach-6 quiet tunnel is the first operational hypersonic quiet tunnel with low operating costs and good optical access.

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“…Schneider et al [157] report the design and performance of the case 7 bleed-slot geometry, which increased the suction mass flow to 38%. It also reports the polishing of the entire portion of the nozzle downstream of the electroformed throat.…”

Section: Shakedown and Modifications For Quiet Flowmentioning

confidence: 99%

“…However, the tunnel remained quiet only below 8 psia (55 kPa), with no change in the quiet pressure, although there appeared to be some reduction in the noise under quiet conditions. Under some conditions, separation seems to have occurred in the nozzle-wall boundary layers when they became laminar as the pressure dropped during the run ( [157], Fig. 11 and pp.…”

Section: Shakedown and Modifications For Quiet Flowmentioning

confidence: 99%

Development of Hypersonic Quiet Tunnels

Schneider

2008

Journal of Spacecraft and Rockets

217

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Since then, he has focused on high-speed boundary-layer transition, developing facilities and instrumentation for detailed measurements under quiet-flow conditions. A $1 million 9.5-in. Mach-6 quiet-flow Ludwieg tube was completed in 2001 and achieved high Reynolds number quiet flow in 2006. He was promoted to professor, School of Aeronautics and Astronautics, in 2004, and has written seven review articles on hypersonic transition. He is an Associate Fellow of AIAA.

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Hypersonic Stability and Transition Experiments on Blunt Cones and a Generic Scramjet Forebody

Cited by 11 publications

References 40 publications

Streamwise Vortex Instability and Transition on the Hyper-2000 Scramjet Forebody

Streamwise Vortex Instability and Transition on the Hyper-2000 Scramjet Forebody

Quiet-Flow Ludwieg Tube for Hypersonic Transition Research

Development of Hypersonic Quiet Tunnels

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