Design and characterization of the Sandia free-piston reflected shock tunnel

Lynch, Kyle P.; Grasser, Thomas W.; Spillers, Russell Wayne; Downing, C.; Daniel, Kyle; Jans, Elijah; Kearney, Sean P.; Morreale, Bryan D.; Wagnild, Ross; Wagner, Justin L.

doi:10.1007/s00193-023-01127-4

Cited by 3 publications

(1 citation statement)

References 28 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The half-angle of the conical nozzles used on hypersonic impulse facilities, past and present, varies between 5.8 • and 15 • , as shown in figure 1. Depending on the relative size of (Zeitoun et al 1994), JF-10 (Zhao et al 2005), T5 (Marineau & Hornung 2009), NASA Ames reflected shock tunnel (RST) (Menees 1972), Hypulse (Chue et al 2003), Cornell Aeronautical Laboratory (CAL) RST (Hall & Russo 1966), FD-21 (Shen et al 2023), Sandia RST (Lynch et al 2023), HEG (Hannemann et al 2018), Delft Ludwieg tube (LT) (Schrijer & Bannink 2010), L3K (Gülhan et al 2018), HIEST (Tanno & Itoh 2018), T3 (Mallinson, Gai & Mudford 1996), T-ADFA (Krishna, Sheehe & O'Byrne 2018), TH2 (Gu et al 2022) and NASA Langley expansion tunnel (ET) (Miller 1977).…”

Section: Introductionmentioning

confidence: 99%

The influence of hypersonic free-stream conicity on the flow over a sphere

Gu,

Wen,

Hao

et al. 2024

J. Fluid Mech.

View full text Add to dashboard Cite

The influence of free-stream conicity on the various aspects of the flow over a spherical test model is examined using both analytical and numerical methods. For the analytical method, a simple closed-form analytical model is assembled. Six different free-stream conditions with different Mach numbers, Reynolds numbers and thermochemistry are tested at four different degrees of conicity corresponding to those which can realistically be encountered in experiments. It is found that the results around the stagnation point are mostly insensitive to the flow condition and gas type, except for some mild non-equilibrium effects, and excellent agreement between the analytical and numerical results exists. The shock stand-off distance on the stagnation streamline is shown to decrease with increasing conicity. This decrease increases the tangential velocity gradient at the stagnation point, increasing the stagnation point heat flux and decreasing the stagnation point boundary layer thickness. The free-stream conicity is also found to alter the normalized distributions of the shock stand-off distance, heat flux, surface pressure and boundary layer thickness with the angle from the stagnation point. In general, increasing the conicity magnifies the slope of these distributions. Regarding the boundary layer transition, it is found that, if it occurs in a uniform free stream, it would also occur in a conical free stream, albeit with the transition point shifted upstream closer to the stagnation point due to the increase in the boundary layer edge tangential velocity. Overall, considering the relevant experimental uncertainties, corrections for free-stream conicity are generally recommended when larger test models are used.

show abstract

Section: Introductionmentioning

confidence: 99%

The influence of hypersonic free-stream conicity on the flow over a sphere

Gu,

Wen,

Hao

et al. 2024

J. Fluid Mech.

View full text Add to dashboard Cite

show abstract

Arrays of glass wedges for multi-dimensional optical diagnostics

Richardson

2023

Appl. Opt.

View full text Add to dashboard Cite

There is a common need in the advancement of optical diagnostic techniques to increase the dimensionality of measurements. For example, point measurements could be improved to multi-point, line, planar, volumetric, or time-resolved volumetric measurements. In this work, a unique optical element is presented to enable multi-dimensional measurements, namely, an array of glass wedges. A light source is passed through the wedges, and different portions of the illumination are refracted by different amounts depending on the glass wedge angle. Subsequent optics can be used to focus the light to multiple points, lines, or planes. Basic characterization of a glass wedge array is presented. Additional wedge-array configurations are discussed, including the use of a periodic intensity mask for multi-planar measurements via structured illumination. The utility of this optical element is briefly demonstrated in (a) multi-planar flame particulate measurements, (b) multi-point femtosecond-laser electronic excitation tagging for flow velocimetry, and (c) multi-line nitric oxide molecular tagging velocimetry in a hypersonic shock-tunnel. One significant advantage of this optical component is its compatibility with high-energy laser sources, which may be a limiting factor with other beam-splitting or beam-forming elements such as some diffractive optics. Additionally, an array of glass wedges is simple and easily customizable compared to other methods for forming multiple closely spaced illumination patterns. Suggestions for further development and applications are discussed.

show abstract