Laser-induced resonance in a forward-facing cavity at Mach 4

Ladoon, D.; Schmisseur, John D.; Schneider, Steven P.

doi:10.2514/6.1997-339

Cited by 4 publications

(2 citation statements)

References 15 publications

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“…These quiet-flow results also show that the basic concept for the facility is sound. Recent work has shown that controlled perturbers and diagnostic instrumentation Figure 1: Schematic of Purdue Mach-4 Quiet-Flow Ludwieg Tube can be developed and operated in the facility, and that useful instability measurements can be obtained [58,53,36,37]. Operation with quiet flow at higher Reynolds numbers now requires only a larger and higher quality test section.…”

Section: The Purdue Quiet-flow Ludwieg Tubementioning

confidence: 99%

Design of a Mach-6 quiet-flow wind-tunnel nozzle using the e**N method for transition estimation

Schneider

1998

36th AIAA Aerospace Sciences Meeting and Exhibit

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A high Reynolds-number Mach-6 quiet-flow windtunnel nozzle has been designed for a new quietflow Ludwieg tube. The quiet-flow nozzle is designed to maintain laminar boundary layers on the nozzle walls as far downstream as possible. A very long nozzle with gentle curvature is used to reduce Görtler instability. Early transition would occur in adiabatic nozzles of this type, due to the first-mode TS instability. This is controlled with an isothermal wall temperature that is high near the throat and tapers to ambient near the exit. The crossflow instability is eliminated through use of an axisymmetric nozzle. Predictions using e N techniques suggest that a quiet-flow Reynolds number in excess of 13 million can be achieved in a 103-inch-long 9-inch-diameter prototype nozzle at 10 atm. total pressure. This performance would be about twice that of the existing Langley Mach-6 quiet-flow nozzle. A 33-foot-long 24-inch nozzle at the same pressure is predicted to have a quiet Reynolds number of more than 36 million, a value sufficient to allow reproducing many flight experiments.

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Section: The Purdue Quiet-flow Ludwieg Tubementioning

confidence: 99%

Design of a Mach-6 quiet-flow wind-tunnel nozzle using the e**N method for transition estimation

Schneider

1998

36th AIAA Aerospace Sciences Meeting and Exhibit

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“…Salyer characterized the perturbation profile across the shock and compared it with the LDI results. The laser system used to generate the laser perturbation in the work done by Salyer [15][16][17][18], Schmisseur [21], and Ladoon [22,23] could not be readily resurrected for this project, so it could not be used to test the performance of the LDI.…”

Section: Motivation and Backgroundmentioning

confidence: 99%

Oscillations in a Forward-Facing Cavity Measured Using Laser-Differential Interferometry in a Hypersonic Quiet Tunnel

Segura¹

2007

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AFOSR/NAUnclassified and Approved for Public Release M.S. thesis by Rodrigo Segura with development of LDI for Mach-6 quiet tunnel and measurements in Mach-4 quiet tunnel Laminar-turbulent transition is a pivotal factor for the design of hypersonic vehicles but the mechanisms that induce transition are not well understood. A laser differential interferometer (LDI) is a non-intrusive optical device that measures the optical path length difference between two laser beams. The LDI is a reliable calibrated instrument to assist the study of boundary layer instability-wave growth in hypersonic flow and has high sensitivity and frequency response. An LDI with a commercial balanced photodetector capable of detecting optical path length differences of lambda/21,000 from DC to 80 MHz was assembled and tested in the Purdue Quiet-Flow Ludwieg tube. Fluctuations in the subsonic region of a forward-facing cavity were measured with the LDI and compared to those detected with a Kulite pressure transducer at the base of the cavity. Predictions of self-resonating deep cavities were confirmed. The LDI was then adapted and transferred to the Boeing/AFOSR Mach-6 Quiet Tunnel. to give special thanks to Joan Jackson; she made me laugh and was patient and helpful even when I demanded her help on rather short notice. Joe Kline's technical assistance is appreciated.A great deal of contribution came from my fellow researchers.

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