One-dimensional modeling methodology for shock tubes: Application to the EAST facility

Priyadarshini, Maitreyee Sharma; Munafò, Alessandro; Brandis, Aaron M.; Cruden, Brett A.; Panesi, Marco

doi:10.2514/6.2018-4181

Cited by 4 publications

(3 citation statements)

References 6 publications

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“…The second successfully simulated the test slug, but because the driver was not fully modelled the shock deceleration trajectory was not reproduced (Chandel et al 2019). One-dimensional simulation approaches have also been inconclusive (Sharma Priyadarshini et al 2018).…”

Section: Introductionmentioning

confidence: 99%

The influence of shock speed variation on radiation and thermochemistry experiments in shock tubes

Collen¹,

Mare²,

Mare³

et al. 2022

J. Fluid Mech.

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Shock tubes are a crucial source of experimental data for the aerothermodynamic modelling of atmospheric entry vehicles. Notably, many chemical-kinetic and radiative models are validated directly against optical measurements from these facilities. Typically, the incident shock speed at the location of the experimental measurement is taken to be representative of the test slug; however, the shock velocity can vary substantially upstream of this location. These variations have been long posited as a source of disagreement with computational predictions, although a definitive link has proved elusive. This work describes a series of experiments which aim to isolate and confirm the importance of the shock deceleration effect. This is achieved by generating different shock trajectories and comparing the post-shock trends in atomic oxygen emission and electron density. These trends are shown to be directly linked to the upstream shock speed variations using a recently developed numerical tool (LASTA). The close agreement of the comparisons confirms the importance of shock speed variation for shock tube experiments; these findings have direct and potentially critical relevance for all such studies, both past and present.

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Section: Introductionmentioning

confidence: 99%

The influence of shock speed variation on radiation and thermochemistry experiments in shock tubes

Collen¹,

Mare²,

Mare³

et al. 2022

J. Fluid Mech.

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“…However, this problem can also arise with other states such as N 2 (C), especially in the early phase of a discharge [9,10] or when argon is present [4,11]. Examples also exist in high enthalpy flows where thermal equilibrium (electron temperature equal to gas temperature) persists [12][13][14]. In previous work [15,16], the authors measured the rotational temperatures of the N 2…”

Section: Introductionmentioning

confidence: 99%

Inferring gas temperature from N₂ emission via rotational distribution of the N₂ B³Π_g and C³Π_u states

Tibère-Inglesse

McGuire

Laux

2023

Plasma Sources Sci. Technol.

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Optical Emission Spectroscopy (OES) has been frequently used to measure the rotational temperature of a plasma. The technique is relatively simple to implement and non-intrusive. However, in the visible and ultraviolet spectral regions, it relies on emission from excited vibronic states whose rotational and vibrational temperatures might not be equilibrated with the bulk temperature of the plasma. Oftentimes, rapid equilibration between the rotational and translational modes occurs so that these temperatures are equilibrated. However, many cases exist where these modes are not equilibrated. In this work, we have developed a simple model that can be used as an experimental tool when using OES. This model helps identify whether equilibration between rotational and translational modes is expected. In cases where non-equilibrium is expected, the model may be used to provide an estimate of the bulk gas temperature. An illustrative example is given where we use this model to analyze previous measurements made in a thermal nonequilibrium discharge.

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“…A similar method may be performed to characterize the stagnation-line flow on a large blunt body as an analogy to the post-shock flow, which is a method currently employed by the group at NASA Ames [13]. Many researchers have performed full facility simulations of the shock tube to try to incorporate the more complex effects of driver and boundary layer growth, the simplest being one-dimensional models, such as L1d by Jacobs et al [14,15] and Sharma et al [16], which have simplified models of the boundary layer growth that alter the shock speed and gas slice locations. Simulation complexity may be expanded up to fully two-dimensional simulations of the entire facility, incorporating numerical models of the transient driver and diaphragm opening, which account for the larger proportion of shock speed variation effects [17,18].…”

Section: Introductionmentioning

confidence: 99%

Analytical Method of Evaluating Nonuniformities in Shock Tube Flows: Theory and Development

McGilvray

Mare

2022

AIAA Journal

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Shock tube experiments are a cornerstone of investigations into the hypersonic flight environment. However, the actual flow through the basic shock tube has not been well characterised in the literature, and nonuniformities arising in the test gases are not well understood. This work produces a quasi-one-dimensional analytical methodology for predicting the nonuniformities in the post-shock test gas based exclusively on the experimentally measured history of shock speed down the tube. Wave effects extracted from shock speed variations are shown to provide all information necessary in order to reconstruct the test slug from any particular experiment. Accurate representation of flow dynamics is initially checked against Argon test cases following accelerating and decelerating shock trajectories, each with a tube-end Mach number of 6.5 and a fill pressure of 66.66 Pa in a tube of 100 mm diameter. Agreement between the method and results from a viscous, axisymmetric Navier-Stokes solution is found to within 1% in pressure and temperature.

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One-dimensional modeling methodology for shock tubes: Application to the EAST facility

Cited by 4 publications

References 6 publications

The influence of shock speed variation on radiation and thermochemistry experiments in shock tubes

The influence of shock speed variation on radiation and thermochemistry experiments in shock tubes

Inferring gas temperature from N₂ emission via rotational distribution of the N₂ B³Π_g and C³Π_u states

Analytical Method of Evaluating Nonuniformities in Shock Tube Flows: Theory and Development

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One-dimensional modeling methodology for shock tubes: Application to the EAST facility

Cited by 4 publications

References 6 publications

The influence of shock speed variation on radiation and thermochemistry experiments in shock tubes

The influence of shock speed variation on radiation and thermochemistry experiments in shock tubes

Inferring gas temperature from N2 emission via rotational distribution of the N2 B3Πg and C3Πu states

Analytical Method of Evaluating Nonuniformities in Shock Tube Flows: Theory and Development

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Inferring gas temperature from N₂ emission via rotational distribution of the N₂ B³Π_g and C³Π_u states