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NO PLIF Study of Hypersonic Transition Over a Discrete Hemispherical Roughness ElementNitric oxide (NO) planar laser-induced fluorescence (PLIF) has been use to investigate the hypersonic flow over a flat plate with and without a 2-mm (0.08-in) radius hemispherical trip. In the absence of the trip, for all angles of attack and two different Reynolds numbers, the flow was observed to be laminar and mostly steady. Boundary layer thicknesses based on the observed PLIF intensity were measured and compared with a CFD computation, showing agreement. The PLIF boundary layer thickness remained constant while the NO flowrate was varied by a factor of 3, indicating non-perturbative seeding of NO. With the hemispherical trip in place, the flow was observed to be laminar but unsteady at the shallowest angle of attack and lowest Reynolds number and appeared vigorously turbulent at the steepest angle of attack and highest Reynolds number. Laminar corkscrew-shaped vortices oriented in the streamwise direction were frequently observed to transition the flow to more turbulent structures.
Document ID
20090033105
Acquisition Source
Langley Research Center
Document Type
Conference Paper
Authors
Danehy, Paul M. (NASA Langley Research Center Hampton, VA, United States)
Bathel, Brett F. (Virginia Univ. Charlottesville, VA, United States)
Ivey, Christopher (Johns Hopkins Univ. MD, United States)
Inman, Jennifer A. (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
January 5, 2009
Subject Category
Aerodynamics
Report/Patent Number
AIAA Paper 2009-0394
LF99-7115
Meeting Information
Meeting: 47th AIAA Aerospace Sciences Meeting and Exhibit
Location: Orlando, FL
Country: United States
Start Date: January 5, 2009
End Date: January 8, 2009
Sponsors: American Inst. of Aeronautics and Astronautics
Funding Number(s)
WBS: WBS 599489.02.07.07.06.03
Distribution Limits
Public
Copyright
Public Use Permitted.

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