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Air Density Measurements in a Mach 10 Wake Using Iodine Cordes BandsAn exploratory study designed to examine the viability of making air density measurements in a Mach 10 flow using laser-induced fluorescence of the iodine Cordes bands is presented. Experiments are performed in the NASA Langley Research Center 31 in. Mach 10 air wind tunnel in the hypersonic near wake of a multipurpose crew vehicle model. To introduce iodine into the wake, a 0.5% iodine/nitrogen mixture is seeded using a pressure tap at the rear of the model. Air density was measured at 56 points along a 7 mm line and three stagnation pressures of 6.21, 8.62, and 10.0 MPa (900, 1250, and 1450 psi). Average results over time and space show rho(sub wake)/rho(sub freestream) of 0.145 plus or minus 0.010, independent of freestream air density. Average off-body results over time and space agree to better than 7.5% with computed densities from onbody pressure measurements. Densities measured during a single 60 s run at 10.0 MPa are time-dependent and steadily decrease by 15%. This decrease is attributed to model forebody heating by the flow.
Document ID
20120012055
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Balla, Robert J. (NASA Langley Research Center Hampton, VA, United States)
Everhart, Joel L. (NASA Langley Research Center Hampton, VA, United States)
Date Acquired
August 26, 2013
Publication Date
June 1, 2012
Publication Information
Publication: AIAA Journal
Volume: 50
Issue: 6
Subject Category
Fluid Mechanics and Thermodynamics
Report/Patent Number
NF1676L-12551
Funding Number(s)
WBS: WBS 599489.02.07.07.03.12.01
Distribution Limits
Public
Copyright
Other