Experiments on shock stand-off distance in non-equilibrium flow

Wegener, Peter P.; Buzyna, George

doi:10.1017/s0022112069000577

Cited by 22 publications

(10 citation statements)

References 20 publications

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“…This flowfield provides additional verification of facility operation via numerical simulations and thermochemical calculations with a relatively simple geometry. Shock standoff distances over a sphere have been previously investigated in nonequilibrium air and nitrogen flows [38,43]. As discussed in Sec.…”

Section: B Sphere Shock Shapesmentioning

confidence: 99%

Experimental and Numerical Investigation of Hypervelocity Carbon Dioxide Flow over Blunt Bodies

Sharma¹,

Swantek²,

Flaherty³

et al. 2010

Journal of Thermophysics and Heat Transfer

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This paper represents ongoing efforts to study high-enthalpy carbon dioxide flows in anticipation of the upcoming Mars Science Laboratory and future missions. The work is motivated by observed anomalies between experimental and numerical studies in hypervelocity impulse facilities. In this study, experiments are conducted in the hypervelocity expansion tube that, by virtue of its flow acceleration process, exhibits minimal freestream dissociation in comparison with reflected shock tunnels, simplifying comparison with simulations. Shock shapes of the laboratory aeroshell at angles of attack of 0, 11, and 16 deg and spherical geometries are in very good agreement with simulations incorporating detailed thermochemical modeling. Laboratory shock shapes at a 0 deg of attack are also in good agreement with data from the LENS X expansion tunnel facility, confirming results are facility-independent for the same type of flow acceleration. The shock standoff distance is sensitive to the thermochemical state and is used as an experimental measurable for comparison with simulations and two different theoretical models. For low-density small-scale experiments, it is seen that models based upon assumptions of large binary scaling values do not match the experimental and numerical results. In an effort to address surface chemistry issues arising in high-enthalpy groundtest experiments, spherical stagnation point and aeroshell heat transfer distributions are also compared with the simulation. Heat transfer distributions over the aeroshell at the three angles of attack are in reasonable agreement with simulations, and the data fall within the noncatalytic and supercatalytic solutions.

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Section: B Sphere Shock Shapesmentioning

confidence: 99%

Experimental and Numerical Investigation of Hypervelocity Carbon Dioxide Flow over Blunt Bodies

Sharma¹,

Swantek²,

Flaherty³

et al. 2010

Journal of Thermophysics and Heat Transfer

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“…The starting point of the time scale roughly coincides with rupture of the diaphragm. Measured starting time, t , is taken to be *s = *2 " *1 • (5) where tj is the time at which the expansion wave arrives at the exit, and t 2 is the time at which constant pressure is established there. Note that t is not the total starting time, t., as defined in Figure s l. In this case…”

Section: Resultsmentioning

confidence: 99%

Effects of Nozzle Geometry and Diaphragm Location on the Starting Process in a Ludwieg Tube

Smith¹,

Mosnier²

1973

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“…Shock stand-off distances over a sphere have been previously investigated in nonequilibrium air and nitrogen flows. 31,36 As discussed in Section I, Wen and Hornung measured shock stand-off distances over spheres in a high-enthalpy carbon dioxide flow field. 1 Outstanding issues in a carbon dioxide flowfield still remain, including the role of thermochemical energy storage and transfer and the possibility of facility-specific data.…”

Section: B Sphere Shock Shapesmentioning

confidence: 99%

Evaluation of Hypervelocity Carbon Dioxide Blunt Body Experiments in an Expansion Tube Facility

Sharma

Swantek

Flaherty

et al. 2011

49th AIAA Aerospace Sciences Meeting Including the New Horizons Forum and Aerospace Exposition

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This work represents efforts to study high-enthalpy carbon dioxide flows in anticipation of the upcoming Mars Science Laboratory (MSL) and future missions. The current study extends the previous presentation of experimental results by the comparison now with axisymmetric simulations incorporating detailed thermochemical modeling. The work is motivated by observed anomalies between experimental and numerical studies in hypervelocity impulse facilities. In this work, experiments are conducted in the Hypervelocity Expansion Tube (HET) which, by virtue of its flow acceleration process, exhibits minimal freestream dissociation in comparison to reflected shock tunnels. This simplifies the comparison with computational result as freestream dissociation and considerable thermochemical excitation can be neglected. Shock shapes of the Laboratory aeroshell and spherical geometries are compared with numerical simulations. In an effort to address surface chemistry issues arising from high-enthalpy carbon dioxide ground-test based experiments, spherical stagnation point and aeroshell heat transfer distributions are also compared with simulation. The shock stand-off distance has been identified in the past as sensitive to the thermochemical state and as such, is used here as an experimental measureable for comparison with CFD and two different theoretical models. For low-density, small-scale experiments it is seen that models based upon assumptions of large binary scaling values are unable to match the experimental and numerical results. Very good agreement between experiment and CFD is seen for all shock shapes and heat transfer distributions fall within the non-catalytic and super-catalytic solutions.

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Experiments on shock stand-off distance in non-equilibrium flow

Cited by 22 publications

References 20 publications

Experimental and Numerical Investigation of Hypervelocity Carbon Dioxide Flow over Blunt Bodies

Experimental and Numerical Investigation of Hypervelocity Carbon Dioxide Flow over Blunt Bodies

Effects of Nozzle Geometry and Diaphragm Location on the Starting Process in a Ludwieg Tube

Evaluation of Hypervelocity Carbon Dioxide Blunt Body Experiments in an Expansion Tube Facility

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