Construction of a Mach 7 Ludwieg Tube at UTSA

Hoffman, Eugene N.; Bashor, Ian; Combs, Christopher S.

doi:10.2514/6.2020-2998

Cited by 4 publications

(1 citation statement)

References 18 publications

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“…A 6 m 3 (1600 gallon) vacuum tank is used with the facility to achieve the desired number of steady-state passes and test duration. An indepth discussion of this facility, the motivation behind the various design choices, and a detailed discussion of the individual components are provided by Bashor et al [35], and Hoffman et al [36,37].…”

Section: Methodsmentioning

confidence: 99%

Flow Characterization of the UTSA Hypersonic Ludwieg Tube

et al. 2023

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The characterization of a hypersonic impulse facility is performed using a variety of methods including Pitot probe scans, particle image velocimetry, and schlieren imaging to verify properties such as the velocity, Mach number, wall boundary layer thickness, and freestream turbulence intensity levels. The experimental results are compared to the numerical simulations of the facility performed with Ansys Fluent to compare the design and operational conditions. The presentation of results in this manuscript is prefaced by a description of the facility and its capabilities. The UTSA Ludwieg tube facility can produce a hypersonic freestream flow with a Mach number of 7.2 ± 0.2 and unit Reynolds numbers of up to 200 × 106 m−1. The Pitot probe profiles of the 203-mm-square test section indicate a 152 ± 10 mm square freestream core with turbulence intensity values ranging from 1% to 2%. Schlieren imaging of the oblique shockwaves on a 15° wedge model provided an alternate means of verifying the Mach number. Particle image velocimetry and previous molecular tagging velocimetry results showed a good agreement with the Pitot probe data and numerical simulations in the key parameters including freestream velocity, wall boundary layer velocity profiles, and wall boundary layer thickness.

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Section: Methodsmentioning

confidence: 99%

Flow Characterization of the UTSA Hypersonic Ludwieg Tube

et al. 2023

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Forward and Inverse Modeling of Depth-of-Field Effects in Background-Oriented Schlieren

Molnar,

LaLonde,

Combs

et al. 2024

AIAA Journal

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This paper reports a novel cone-ray model of background-oriented schlieren (BOS) imaging that accounts for depth-of-field effects. Reconstructions of the density field performed with this model are far more robust to the blur associated with a finite aperture than conventional reconstructions, which presume a thin-ray pinhole camera. Our model is characterized and validated using forward evaluations of simulated buoyancy-driven flow and both simulated and experimental BOS measurements of hypersonic flow over a sphere. Moreover, the model is embedded in a neural reconstruction algorithm, which is demonstrated with a total variation penalty and the compressible Euler equations. Our cone-ray technique dramatically improves the accuracy of BOS reconstructions: the shock interface is well-resolved in all our tests, irrespective of the camera’s aperture setting, which spans f-numbers from 22 down to 4.

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