Journal ArticleDOI
The influence of boundary layer growth on shock tube test times
P. J. Musgrove,J. P. Appleton +1 more
TLDR
In this paper, a linearised solution of the unsteady one-dimensional conservation equations is obtained which describes the variations in the average flow properties external to the boundary layer, and a simple method of estimating shock tube test times is outlined, based on self similar solutions of the constant shock speed analysis.Abstract:
A theoretical and experimental investigation of the limitation on shock tube test times which is caused by the development of laminar and turbulent boundary layers behind the incident shock is presented. Two theoretical methods of predicting the test time have been developed. In the first a linearised solution of the unsteady one-dimensional conservation equations is obtained which describes the variations in the average flow properties external to the boundary layer. The boundary layer growth behind the shock is related to the actual extent of the hot flow and not, as in previous unsteady analyses, to its ideal extent. This new unsteady analysis is consequently not restricted to regions close to the diaphragm. Shock tube test times are determined from calculations of the perturbed shock and interface trajectories. In the second method a constant velocity shock is assumed and test times are determined by approximately satisfying only the condition of mass continuity between the shock and the interface. A critical comparison is made between this and previous theories which assume a constant velocity shock. Test times predicted by the constant shock speed theory are generally in agreement with those predicted by the unsteady theory, although the latter predicts a transient maximum test time in excess of the final asymptotic value. Shock tube test times have also been measured over a wide range of operating conditions and these measurements, supplemented by those reported elsewhere, are compared with the predictions of the theories; good agreement is generally obtained. Finally, a simple method of estimating shock tube test times is outlined, based on self similar solutions of the constant shock speed analysis.read more
Citations
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Journal ArticleDOI
Detonation propagation with velocity deficits in narrow channels
Kazuhiro Ishii,M. Monwar +1 more
TL;DR: In this article, the propagation limits of detonations in narrow channels have been studied with a focus on velocity deficits and variation in cell widths, and it was found that for given mixtures, a combination of the calculated velocity deficit and the number of cells in a channel contributes to the prediction of propagation limits.
Journal ArticleDOI
Excitation Mechanisms of the Nitrogen Frist‐Positive and First‐Negative Radiation at High Temperature
TL;DR: In this paper, the kinetic mechanisms responsible for the excitation of the first positive and first negative emission of nitrogen have been investigated in a re-examination of previously reported shock-tube measurements of the nonequilibrium radiation for these systems.
Journal ArticleDOI
Interaction between the Unsteady Boundary Layer and Inviscid Hot Flow in a Shock Tube
David E. Zeitoun,M. Imbert +1 more
TL;DR: In this paper, a numerical calculation for the flow in a low-pressure shock tube is presented, where the evolution of the hot flow quantities due to mutual interaction between the boundary layer and inviscid hot flow are taken into account.
Journal ArticleDOI
Experimental verification of effects of turbulent Boundary layers on chemical-kinetic measurements in a shock tube
F.E. Belles,T.A. Brabbs +1 more
TL;DR: Turbulent boundary layer effects on chemical and kinetic measurements of gas mixture composition from nonuniform shock tube flow were studied in this article, where they showed that the boundary layer effect can affect both chemical and physical measurements.
Journal ArticleDOI
Chemical thermometry in miniature HRRST using 1,1,1-trifluoroethane dissociation
Patrick Lynch,Guanyu Wang +1 more
TL;DR: In this article, the decomposition of 1,1,1-trifluoroethane (C2H3F3) was measured in a 12.7 mm bore high repetition rate miniature shock tube (7.8 < P5 < 10.6 bar and 1250 < T5 < 1600 K).
References
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Journal ArticleDOI
Test time in low pressure shock tubes
TL;DR: In this paper, the reduction of test time in low pressure shock tubes, due to a laminar wall boundary layer, has been analytically investigated, and it was found that β is considerably larger than the estimates made by Roshko and Hooker except for very strong shocks.
Journal ArticleDOI
Shock Tube Test Time Limitation Due to Turbulent-Wall Boundary Layer
TL;DR: In this article, the authors investigated the test time limitation due to the premature arrival of the contact surface of the boundary layer and compared the results with those for wholly laminar-wall boundary layers, and found that, for a given shock Mach number, the maximum possible test time (in a long shock tube) varies as d 6/4p co1/4 and d2p CD for both air and argon.
Journal ArticleDOI
Shock‐Tube Performance at Low Initial Pressure
TL;DR: In this article, an electron beam densitometer has been used to investigate the behavior of a conventional 1⅛in. i.d. shock tube operating at initial pressures of the order of 1 mm Hg.
Journal ArticleDOI
On Flow Duration in Low‐Pressure Shock Tubes
TL;DR: In this paper, the maximum possible flow duration τm in a shock tube is determined; it increases linearly with the initial pressure and the square of the tube diameter and decreases strongly with shock Mach number.
Journal ArticleDOI
Influence of diaphragm opening time on shock-tube flows
TL;DR: In this paper, the authors used the equilibrium Hugoniotiot for the driven gas, both for the usual model of shock tube flow and for a suggested model based on a finite rupture time for the diaphragm.
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