Multiple Velocity Profile Measurements in Hypersonic Flows Using Sequentially-Imaged Fluorescence Tagging

Bathel, Brett F.; Danehy, Paul M.; Inman, Jennifer A.; Jones, Stephen B.; Ivey, Christopher B.; Goyne, Christopher P.

doi:10.2514/6.2010-1404

Cited by 18 publications

(28 citation statements)

References 14 publications

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“…13. However, three modifications have been made to the velocity and uncertainty processing analys and are worth discussing here.…”

Section: B Velocity and Uncertainty Analysismentioning

confidence: 99%

“…Previous velocity measurements reported (Ref. 13) were made using a fixed-size, fixed-location correlation window. However, for large measured velocities, the potential for truncating the right edge of the delayed profile existed.…”

Section: B Velocity and Uncertainty Analysismentioning

confidence: 99%

“…A detailed discussion of the timing sequence methodology used in the NO PLIF experiments is provided in Ref. 13.…”

Section: Plif Imaging Systemmentioning

confidence: 99%

“…For the 500 ns gate delay, this level was experimentally determined to be approximately 1/126 th of the undelayed image. 13 Therefore, this fraction of the undelayed image was also subtracted from the delayed image in addition to the normal background offset level. Care was taken over the course of the experiment to avoid saturation of the CCD signal.…”

Section: Image Processing and Analysis A Initial Image Processingmentioning

confidence: 99%

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Hypersonic Laminar Boundary Layer Velocimetry with Discrete Roughness on a Flat Plate

Bathel

Danehy

Inman

et al. 2010

40th Fluid Dynamics Conference and Exhibit

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Laminar boundary layer velocity measurements are made on a 10-degree half-angle wedge in a Mach 10 flow. Two types of discrete boundary layer trips were used to perturb the boundary layer gas. The first was a 2-mm tall, 4-mm diameter cylindrical trip. To study the precision of the measurement technique, the angle of attack was varied during one run. Nitric-oxide (NO) molecular tagging velocimetry (MTV) was used to obtain averaged axial velocity values and associated uncertainties. These uncertainties are as low as 20 m/s. An interline, progressive scan CCD camera was used to obtain separate images of the initial reference and shifted NO molecules that had been tagged by the laser. The CCD configuration allowed for sub-microsecond sequential acquisition of both images. The maximum planar spatial resolution achieved for the side-view velocity measurements was 0.07-mm in the wall-normal direction by 1.45-mm in the streamwise direction with a spatial depth of 0.5-mm. For the plan-view measurements, the maximum planar spatial resolution in the spanwise and streamwise directions was 0.69-mm by 1.28-mm, respectively, with a

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“…13. However, three modifications have been made to the velocity and uncertainty processing analys and are worth discussing here.…”

Section: B Velocity and Uncertainty Analysismentioning

confidence: 99%

Section: B Velocity and Uncertainty Analysismentioning

confidence: 99%

“…A detailed discussion of the timing sequence methodology used in the NO PLIF experiments is provided in Ref. 13.…”

Section: Plif Imaging Systemmentioning

confidence: 99%

Section: Image Processing and Analysis A Initial Image Processingmentioning

confidence: 99%

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Hypersonic Laminar Boundary Layer Velocimetry with Discrete Roughness on a Flat Plate

Bathel

Danehy

Inman

et al. 2010

40th Fluid Dynamics Conference and Exhibit

Self Cite

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show abstract

“…A detailed discussion of the timing sequence methodology used in the NO PLIF experiments is provided in Ref. 10. The magnification of the images (pixels/mm) factors directly into the measurement of the velocity, and into the error analysis.…”

Section: Molecular Tagging Velocimetry (Mtv) For Axial Velocity Mementioning

confidence: 99%

Nitric Oxide PLIF Measurements in the Hypersonic Materials Environmental Test System (HYMETS)

Inman

Bathel

Johansen

et al. 2011

49th AIAA Aerospace Sciences Meeting Including the New Horizons Forum and Aerospace Exposition

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A nonintrusive laser-based measurement system has been applied for the first time in the HYMETS (Hypersonic Materials Environmental Test System) 400 kW arc-heated wind tunnel at NASA Langley Research Center. Planar laser-induced fluorescence of naturally occurring nitric oxide (NO) has been used to obtain instantaneous flow visualization images, and to make both radial and axial velocity measurements. Results are presented at selected facility run conditions, including some in simulated Earth atmosphere (75% nitrogen, 20% oxygen, 5% argon) and others in simulated Martian atmosphere (71% carbon dioxide, 24% nitrogen, 5% argon), for bulk enthalpies ranging from 6.5 MJ/kg to 18.4 MJ/kg. Flow visualization images reveal the presence of large scale unsteady flow structures, and indicate nitric oxide fluorescence signal over more than 70% of the core flow for bulk enthalpies below about 11 MJ/kg, but over less than 10% of the core flow for bulk enthalpies above about 16 MJ/kg. Axial velocimetry was performed using molecular tagging velocimetry (MTV). Axial velocities of about 3 km/s were measured along the centerline. Radial velocimetry was performed by scanning the wavelength of the narrowband laser and analyzing the resulting Doppler shift. Radial velocities of ±0.5km/s were measured.

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Experimental analysis on the effects of DC arc discharges at various flow regimes

et al. 2015

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This paper addresses the control of the boundary layer on a compression ramp by means of DC electrical arc discharges. The development and realization of the control system are first described and then assessed in the wind tunnel. The objective of the research was to control the supersonic flow using the minimum amount of energy. The array of electrodes was located at the base of a ramp, where a low momentum flow develops. The electrical discharge was generated by a custom designed electronic facility based on high-voltage ignition coils. The slanted tungsten electrodes were insulated by mounting them in a ceramic support. The discharge evolution was studied through high-speed flow visualizations, while electrical measurements at the high-voltage section of the circuitry allowed to estimate the energy release. The development of a high-speed short exposure Schlieren imaging technique, based on a very short duration laser pulse illumination and a double shot CCD camera, allowed to observe the macroscopic effects associated with the arc establishment between the electrodes (glow, sound wave and heat release). Due to the long residence time, the thermal perturbation spread along the streamwise direction. Cross correlation of Schlieren images with short time separation revealed that in supersonic conditions, the discharges led to an overall acceleration of the flow field underneath the oblique shock wave. C 2015 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution 3.0 Unported License.

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Multiple Velocity Profile Measurements in Hypersonic Flows Using Sequentially-Imaged Fluorescence Tagging

Cited by 18 publications

References 14 publications

Hypersonic Laminar Boundary Layer Velocimetry with Discrete Roughness on a Flat Plate

Hypersonic Laminar Boundary Layer Velocimetry with Discrete Roughness on a Flat Plate

Nitric Oxide PLIF Measurements in the Hypersonic Materials Environmental Test System (HYMETS)

Experimental analysis on the effects of DC arc discharges at various flow regimes

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