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Stereoscopic Imaging in Hypersonics Boundary Layers using Planar Laser-Induced FluorescenceStereoscopic time-resolved visualization of three-dimensional structures in a hypersonic flow has been performed for the first time. Nitric Oxide (NO) was seeded into hypersonic boundary layer flows that were designed to transition from laminar to turbulent. A thick laser sheet illuminated and excited the NO, causing spatially-varying fluorescence. Two cameras in a stereoscopic configuration were used to image the fluorescence. The images were processed in a computer visualization environment to provide stereoscopic image pairs. Two methods were used to display these image pairs: a cross-eyed viewing method which can be viewed by naked eyes, and red/blue anaglyphs, which require viewing through red/blue glasses. The images visualized three-dimensional information that would be lost if conventional planar laser-induced fluorescence imaging had been used. Two model configurations were studied in NASA Langley Research Center's 31-Inch Mach 10 Air Wind tunnel. One model was a 10 degree half-angle wedge containing a small protuberance to force the flow to transition. The other model was a 1/3-scale, truncated Hyper-X forebody model with blowing through a series of holes to force the boundary layer flow to transition to turbulence. In the former case, low flowrates of pure NO seeded and marked the boundary layer fluid. In the latter, a trace concentration of NO was seeded into the injected N2 gas. The three-dimensional visualizations have an effective time resolution of about 500 ns, which is fast enough to freeze this hypersonic flow. The 512x512 resolution of the resulting images is much higher than high-speed laser-sheet scanning systems with similar time response, which typically measure 10-20 planes.
Document ID
20080031613
Acquisition Source
Langley Research Center
Document Type
Conference Paper
Authors
Danehy, Paul M. (NASA Langley Research Center Hampton, VA, United States)
Bathel, Brett (Virginia Univ. Charlottesville, VA, United States)
Inman, Jennifer A. (NASA Langley Research Center Hampton, VA, United States)
Alderfer, David W. (NASA Langley Research Center Hampton, VA, United States)
Jones, Stephen B. (NASA Langley Research Center Hampton, VA, United States)
Date Acquired
August 24, 2013
Publication Date
June 23, 2008
Subject Category
Instrumentation And Photography
Report/Patent Number
AIAA 2008-4267
Meeting Information
Meeting: 38th AIAA Fluid Dynamics Conference and Exhibit
Location: Seattle, WA
Country: United States
Start Date: June 23, 2008
End Date: June 26, 2008
Sponsors: American Inst. of Aeronautics and Astronautics
Funding Number(s)
WBS: WBS 599489
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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