Proceedings ArticleDOI
Disturbance and Phase Speed Measurements for Shock Tubes and Hypersonic Boundary-Layer Instability
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TLDR
In this article, the phase speed of disturbances observed in a small shock tube was measured via cross-correlation of successive frames from focusing schlieren videography and double focused laser differential interferometry.Abstract:
Measurements and calculations of the phase speed of disturbances observed in a small shock tube are made, via cross-correlation of successive frames from focusing schlieren videography and double focused laser differential interferometry. The efficacy of the latter technique for measuring slender-body hypersonic boundary-layer instability wave-packets is also demonstrated. Shock tube experiments are performed to provide a known velocity input to both sensors for comparison, and measurements of phase velocity are made behind the reflected shock. Power spectral density curves from the FLDI and focusing schlieren from shock tube experiments at similar conditions are compared with each other and with pitot tube results, and reasonable agreement is found to the frequency limits of the sensors.read more
Citations
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Proceedings ArticleDOI
Disturbance Speed Measurements in a Circular Jet via Double Focused Laser Differential Interferometry
TL;DR: In this article, the phase speed of turbulent jets of three diameters at speeds between 80 m/s and 300m/s, via cross-correlation of signals from a double focused laser differential interferometer (D-FLDI), was measured and calculated using a beam profiler, and the effect of orienting FLDI bundles parallel with and at a 45° angle to the mean flow direction was assessed.
Journal ArticleDOI
Two-point, parallel-beam focused laser differential interferometry with a Nomarski prism.
Brett F. Bathel,Joshua M. Weisberger,Gregory C. Herring,Rudolph A. King,Stephen B. Jones,Richard E. Kennedy,Stuart J. Laurence +6 more
TL;DR: A Nomarski polarizing prism has been used in conjunction with a focused laser differential interferometer to measure the phase velocity of a density disturbance at sampling frequencies ≥10MHz.
Journal ArticleDOI
Measurements of freestream density fluctuations in a hypersonic wind tunnel
TL;DR: In this article, a focused laser differential interferometer (FLDI) was used to measure density disturbances in the freestream of the University of Southern Queensland's Mach 6 wind tunnel.
Journal ArticleDOI
Detection of second-mode instabilities on a flared cone in Mach 6 quiet flow with linear array focused laser differential interferometry
TL;DR: In this article, an enhanced version of the focused laser differential interferometer (FLDI) is used to measure second-mode instabilities in the boundary layer on a flared cone in Mach 6 quiet flow.
References
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Boundary-Layer Linear Stability Theory
TL;DR: In this paper, the amplitude ratio of the most amplified frequency as a function of Reynolds number for a Blasius boundary layer, and found that this quantity had values between five and nine at the observed Ret.
Journal ArticleDOI
Linear Stability Theory and the Problem of Supersonic Boundary- Layer Transition
TL;DR: In this paper, the amplitude ratio of constant-frequency disturbances as a function of Reynolds number for insulated and cooled-wall flat-plate boundary layers between Mach numbers 1.3 and 5.8 is calculated.
Proceedings ArticleDOI
Nosetip bluntness effects on cone frustum boundary layer transition in hypersonic flow
Journal ArticleDOI
Differential Interferometric Measurement of Instability in a Hypervelocity Boundary Layer
TL;DR: In this article, the most unstable mode on a cold-wall slender body at zero angle of incidence is not the viscous instability (as in low-speed boundary layers) but the acoustic instability.
Journal ArticleDOI
Large-Field High-Brightness Focusing Schlieren System
TL;DR: In this paper, the analysis and performance of a large-field high-brightness focusing schlieren system is described and techniques that allow the system to be used even through slightly distorting optical elements.