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Measurements of T5 Shock Tunnel Freestream Temperature, Velocity, and Composition

Finch, Peter M. and Girard, Julian J. and Schwartz, Tal and Strand, Christopher L. and Hanson, Ronald K. and Yu, Wesley M. and Austin, Joanna M. and Hornung, Hans G. (2023) Measurements of T5 Shock Tunnel Freestream Temperature, Velocity, and Composition. AIAA Journal, 61 (4). pp. 1555-1578. ISSN 0001-1452. doi:10.2514/1.j062383.

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We report on measurements of rotational and vibrational temperature, velocity, and concentrations of nitric oxide (NO) in freestream flows at the T5 reflected shock tunnel at California Instistute of Technology. Quantities were measured at 50 kHz by tunable diode laser absorption spectroscopy using five lasers simultaneously to sample 27 quantum state-specific transitions. To isolate core flow measurements from the shear flow surrounding it, optical flow-cutter arms were designed. Two sets of arms with differing optical path lengths were used to assess freestream spatial uniformity. This study consists of nine total experiments (“shots”) spanning four nominal conditions with reservoir enthalpy 8–21 MJ/kg and flow velocity 3.5–5.5 km/s. Freestream measurements generally imply thermal equilibrium of the rotational and vibrational temperatures except at lower-enthalpy conditions. We compare temperature measurements with predictions from five species air simulations and find reasonable agreement at lower-enthalpy conditions but underprediction of NO concentrations. At higher-enthalpy conditions, we observed transitory agreement in temperature but overprediction of NO concentrations. Measured and simulated velocity generally agree well across all conditions. Carbon monoxide, water, and potassium were also detected in the T5 flow, and their concentrations are reported where relevant.

Item Type:Article
Related URLs:
URLURL TypeDescription
Finch, Peter M.0000-0002-6975-6047
Girard, Julian J.0000-0002-8101-015X
Schwartz, Tal0000-0003-0150-9426
Strand, Christopher L.0000-0002-4112-6668
Hanson, Ronald K.0000-0002-8030-5327
Yu, Wesley M.0000-0002-1133-3199
Austin, Joanna M.0000-0003-3129-5035
Hornung, Hans G.0000-0002-4903-8419
Additional Information:© 2023 by the American Institute of Aeronautics and Astronautics, Inc. We would like to acknowledge the help of Bahram Valiferdowsi in running the experiments. This work was supported by the Air Force Office of Scientific Research through grant number FA9550-19-1-0219, with Ivett Leyva and Sarah Popkin as contract monitors. The development of the diagnostic was also supported by the Office of Naval Research through award number N00014-20-1-2322, with Eric Marineau as contract monitor. Fundamental NO spectroscopy research which underlaid this work was supported by Air Force Office of Scientific Research grant number FA9550-18-1-0282, with Brett Pokines as program manager.
Funding AgencyGrant Number
Air Force Office of Scientific Research (AFOSR)FA9550-19-1-0219
Office of Naval Research (ONR)N00014-20-1-2322
Air Force Office of Scientific Research (AFOSR)FA9550-18-1-0282
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Other Numbering System NameOther Numbering System ID
AIAA Paper2021-3525
Issue or Number:4
Record Number:CaltechAUTHORS:20230327-903040000.39
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:120482
Deposited By: George Porter
Deposited On:30 Mar 2023 14:54
Last Modified:30 Mar 2023 15:16

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