Fluorescence Velocimetry of the Hypersonic, Separated Flow over a Cone

Danehy, Paul M.; Mere, P.; Gaston, M.; O’Byrne, Sean; Palma, P. C.; Houwing, A. F. P.

doi:10.2514/2.1450

Cited by 29 publications

(6 citation statements)

References 25 publications

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“…[26][27][28][29][30] Furthermore, researchers have performed experiments in shocktunnels with prescribed shocktube mixtures (≈99% N 2 ≈1% O 2 ) to create ≈1% NO in the free stream for velocimetry. [31][32][33] It should be noted that the VENOM technique [18][19][20][21]30 is also capable of simultaneous temperature measurements.…”

Section: Review and Motivation For Exploration Of Krypton As A Trmentioning

confidence: 98%

Krypton Tagging Velocimetry for Use in High-Speed Ground-Test Facilities

Parziale

Smith

Marineau

2015

53rd AIAA Aerospace Sciences Meeting

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In this work, we present the excitation strategy, experimental setup, and results of an implementation of krypton tagging velocimetry (KTV) as applied to an underexpanded jet of three mixtures. We demonstrate that the KTV technique can be employed with gas mixtures of relatively low krypton concentration (0.5% Kr/99.5% N2) and conclude that the KTV technique shows promise as a velocimetry diagnostic with krypton as an inert, dilute, long-lifetime tracer in gas-phase flows. Nomenclature ∆x Distance traversed by metastable Kr, (m) ∆t Time between the write and read laser Q-switch pulses, (s) V Velocity, (m/s) D Diameter, (m) M Mach number, (-)

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Section: Review and Motivation For Exploration Of Krypton As A Trmentioning

confidence: 98%

Krypton Tagging Velocimetry for Use in High-Speed Ground-Test Facilities

Parziale

Smith

Marineau

2015

53rd AIAA Aerospace Sciences Meeting

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“…Its advantage over PIV techniques in high-speed facilities is that it is not limited by timing issues associated with tracer injection [12] or reduced particle response at Knudsen and Reynolds numbers [4] characteristic of high-speed wind tunnels. Methods of tagging velocimetry include the VENOM [13][14][15][16][17], APART [18][19][20], RELIEF [21][22][23][24][25], FLEET [26,27], STARFLEET [28], PLEET [29], NO [30][31][32][33][34], argon [35], iodine [36,37], sodium [38], acetone [39][40][41], NH [42], and the hydroxyl group techniques [43][44][45][46], among others [47][48][49][50][51][52].…”

Section: Introductionmentioning

confidence: 99%

Single-Laser Krypton Tagging Velocimetry Investigation of Supersonic Air and N2 Boundary-Layer Flows over a Hollow Cylinder in a Shock Tube

2019

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In this paper, we investigate the boundary-layer profiles that form over a sharp, hollow cylinder in supersonic air and N 2 flows with a krypton tagging velocimetry (KTV) single-laser scheme. The supersonic flows are generated by the passage of the primary shock wave over the model in the Stevens shock tube. The experiments are performed in two gas mixtures doped with Kr: 99% N 2 /1% Kr, to model N 2 , and 75% N 2 /20% O 2 /5% Kr, to model air. The experimental setup allows us to vary the pressure and Reynolds number from 3-25 kPa and 1.5 × 10 5 to 1.5 × 10 6 m −1 , respectively, while the Mach number is kept fixed at 1.7. The static temperature and pressure (but not the velocity) are representative of typical large-scale high-enthalpy hypersonic impulse facilities. The KTV data points over the hollow cylinder are mapped to corresponding wall-normal locations above a flat plate, which enables comparison with the similarity solution for compressible boundary-layer flow. Agreement between the similarity solution and experimental results is excellent. Relative to previous two-laser KTV schemes, the single-laser approach used in this work has the advantage of being simpler and more cost effective, but it has a higher laserenergy requirement, 10 mJ/pulse in these experiments. Single-laser KTV is implemented by increasing the energy of the write-laser pulse to a sufficient level such that the Kr becomes partially ionized via a (2 + 1) resonance-enhanced, multiphoton ionization (REMPI) process with an excitation wavelength of 212.6 nm. The write step records the fluorescence that results primarily from the spontaneous emission from the two-photon excitation. After a prescribed delay, the read step records the fluorescence that results from the transitions that follow the recombination process. The signal-to-noise ratio (SNR) is sufficient to extract velocity profiles from single-shot, shock-tube experiments. Two-photon absorption cross-section calculations and emission spectra are presented to justify the chosen excitation wavelength and support our understanding of the Kr excitation and emission scheme.

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“…Although CFD-FASTRAN has been used by several researchers for simulating the shock-tunnelrelated subjects [6,22,23] and to investigate the hypersonic flow regime [24], the current subject has not been tackled previously. As the first step to the numerical study, validation of the CFD-FASTRAN code on this subject was performed by simulating the present experiments [7].…”

Section: Numerical Simulationsmentioning

confidence: 99%

Experimental and Numerical Study of Stationary Throat Plug in Shock Tunnel

Lee

Park

Kwon

2015

Journal of Thermophysics and Heat Transfer

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A throat plug is a device in a shock tunnel to prevent fragments, produced by the bursting of the primary diaphragm, from entering the nozzle and damaging the model. In the present study, a series of experimental and numerical studies has been carried out to investigate the flows around stationary throat plugs in a shock tunnel. For this purpose, conical, circular, and double circular stationary throat plugs that have a 19.4% areal blockage were used as the test models. The primary shock velocity was set at 1.19 km∕s, and the shock generated a tailored condition when helium and air were used as the driver and driven gases at room temperature. In the experiment, the nozzle reservoir pressure and the pitot pressure at the nozzle exit were measured to examine the influence of the throat plug. It was found that, from both the experiment and the calculation, all types of the plugs generate a pressure bump in the nozzle reservoir during the transient period of interaction between the reflected shock and the plugs. After the transient period, the difference between the plug-distorted and -undistorted nozzle flows is small and can practically be neglected. When the driven tube diameter is increased in the region in which the throat plug is located, the pressure bump is almost eliminated. However, according to the calculation, the increased diameter causes an augmentation in the temporal enthalpy and the entropy at the nozzle exit. The spatial distribution of the entropy in the radial direction shows little change. The configuration of the plug has little influence on the shock-tunnel flow when the plug is placed in the region in which the plug does not distort the nozzle flow.

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Fluorescence Velocimetry of the Hypersonic, Separated Flow over a Cone

Cited by 29 publications

References 25 publications

Krypton Tagging Velocimetry for Use in High-Speed Ground-Test Facilities

Krypton Tagging Velocimetry for Use in High-Speed Ground-Test Facilities

Single-Laser Krypton Tagging Velocimetry Investigation of Supersonic Air and N2 Boundary-Layer Flows over a Hollow Cylinder in a Shock Tube

Experimental and Numerical Study of Stationary Throat Plug in Shock Tunnel

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