scholarly journals Validation of the Mach Stem Triple Point

2020 ◽  
Author(s):  
J Johnson-Yurchak
Keyword(s):  
Triple Point ◽  
Mach Stem

PVB Blast Load Enhancement due to Mach Stem

2019 ◽  
Author(s):  
Will Lowry ◽  
Jihui Geng
Keyword(s):  
High Pressure ◽  
Blast Wave ◽  
Triple Point ◽  
Petroleum Refining ◽  
Ground Level ◽  
Chemical Processing ◽  
Mach Stem ◽  
Blast Pressure ◽  
Pressure Region ◽  
High Pressure Region

Abstract A pressure vessel burst (PVB) is an explosion scenario commonly encountered at chemical processing and petroleum refining facilities. Existing methodologies are available to predict the blast loads resulting from a spherical or cylindrical PVB source, with the PVB source either at grade or at an elevation. In the case of an elevated PVB source, the resulting blast wave will reflect from the ground at an angle. This ground level reflection will result in the formation of a Mach stem at certain angles between the incident blast wave and ground, with the required angles dependent on the blast wave overpressure. The triple point associated with the Mach stem moves upwards as the Mach stem progresses forwards, which can create a region of high blast pressure. This paper focuses on the investigation of a methodology that can be used to determine the high-pressure region generated by the Mach stem, along with the associated blast pressure, as a function of the PVB source elevation and incident blast pressure.

Analytical Predictions of Strong Pseudo-Steady Mach Reflections for the Polyatomic Gas: SF6

2001 ◽  
Vol 17 (1) ◽  
pp. 1-12
Author(s):  
J. J. Liu
Keyword(s):  
Mach Number ◽  
Triple Point ◽  
Sulfur Hexafluoride ◽  
Wedge Angle ◽  
Incident Shock ◽  
Mach Stem ◽  
Perfect Gas ◽  
Shock Mach Number ◽  
Stem Curvature ◽  
Trajectory Angle

ABSTRACTStrong pseudo-steady Mach reflections in sulfur hexafluoride (SF6) are analyzed using the three-shock and local three-shock theories, where both the vibrationally-frozen (γ = 1.333) and -equilibrated (γ = 1.093) perfect-gas models are used to compare with existing experiments. The ranges of the incident shock Mach number and reflecting wedge angle studied are 1.49 ≤ Ms ≤ 5.95 and 10° ≤ θω ≤ 42°, respectively. It is found that predicted angles between the incident and reflected shocks from the local three-shock theory using the vibrationally-equilibrated fictitious perfect-gas model (i.e., γ = 1.093) agree closely with those, currently available in literature, measured experimentally; while these predicted angles obtained using the vibrationally-frozen perfect-gas model (i.e., γ = 1.333) differ significantly from the existing experiments. Taking the convex Mach stem curvature at the triple point into consideration, it is shown that both the triple point trajectory angle and the angle between the incident and reflected shocks of strong pseudo-steady Mach reflections in SF6 can be more accurately determined for wide ranges of Ms and θω from the three-shock theory using the vibrationally-equilibrated fictitious perfect-gas model than those without considering this effect.

Time history of regular to Mach reflection transition in steady supersonic flow

2011 ◽  
Vol 682 ◽  
pp. 160-184 ◽  
Author(s):  
S. G. LI ◽  
B. GAO ◽  
Z. N. WU
Keyword(s):  
Triple Point ◽  
Early Stage ◽  
Mach Reflection ◽  
Time History ◽  
Mach Stem ◽  
Interaction Structure ◽  
Reflection Transition ◽  
History Of ◽  
Multiple Interaction ◽  
Mach Waves

In this paper, we study the transition from regular to Mach reflection (RR → MR) in the dual solution domain due to the influence of an upstream disturbance, by considering the transition as an evolutionary rather than an abrupt process. From numerical simulation, we observe for the early stage of transition a multiple interaction structure, composed of a triple-shock structure, a type VI shock interaction and a shock/slipline interaction. In the end, we observe a pure unsteady MR structure. Under self-similar assumption of the triple point for the first stage and including additional Mach waves over the slipline for the last stage, we develop an idealized unsteady model to obtain the evolution of the Mach stem height and the time taken for the Mach stem to stabilize. The triple point is found to move at a nearly constant speed in the multiple interaction stage which occupies about one quarter of the transition time. In the pure unsteady MR stage, which occupies the rest of transition, the speed of the triple point drops nonlinearly until the Mach stem stabilizes.

The structure of the wave front in spinning detonation

1966 ◽  
Vol 26 (2) ◽  
pp. 321-336 ◽  
Author(s):  
D. H. Edwards ◽  
D. J. Parry ◽  
A. T. Jones
Keyword(s):  
Wave Front ◽  
Triple Point ◽  
Experimental Error ◽  
The Self ◽  
Detonation Waves ◽  
Mach Stem ◽  
Spinning Detonation ◽  
Schlieren Photography ◽  
The Waves ◽  
Smoked Foil

The structure and mode of propagation of spinning detonation waves in stoichiometric oxyhydrogen, at initial pressures of 20–30 mm, have been investigated. The waves were generated in a square-section tube and observations have been made by the smoked-film technique, spark schlieren photography and pressure gauges. At the front of the self-sustaining detonation waves obtained at these pressures, two Mach interactions exist, the trajectories of which are derived from the imprints made on the smoked foil. As the triple point traverses the tube section, its direction of motion is found to vary between 50° and 70° with the tube diameter. An analysis of a Mach triple point for these conditions predicts the absence of chemical reaction behind the Mach stem in the immediate neighbourhood of the triple point. Experimentally determined pressures and triple shock angles confirm, to within experimental error, the postulated theoretical configuration.

DECIPHERING THE GEOLOGY AT A PRESUMED TERRANE TRIPLE POINT: GLADSTONE 7.5' QUADRANGLE, CENTRAL VIRGINIA

2020 ◽  
Author(s):  
Ryan T. Walter ◽  
◽  
Evan Laughlin ◽  
Emily R. Hinshaw ◽  
Samuel E. Belding ◽  
...  
Keyword(s):  
Triple Point

scholarly journals Isotopic Composition of Water Used in Triple-Point Cells

2008 ◽  
Vol 29 (3) ◽  
pp. 808-814
Author(s):  
K. S. Gam ◽  
K. H. Kang ◽  
Y.-G. Kim ◽  
I. Yang
Keyword(s):  
Isotopic Composition ◽  
Triple Point

scholarly journals Topological phonons and thermoelectricity in triple-point metals

2018 ◽  
Vol 2 (11) ◽  
Author(s):  
Sobhit Singh ◽  
QuanSheng Wu ◽  
Changming Yue ◽  
Aldo H. Romero ◽  
Alexey A. Soluyanov
Keyword(s):  
Triple Point

A method for predicting Mach stem height in steady flows

2021 ◽  
pp. 095441002110015
Author(s):  
Song-Guk Choe
Keyword(s):  
Analytical Model ◽  
Slip Line ◽  
Flow Region ◽  
Rocket Engines ◽  
Steady Flows ◽  
Mach Stem ◽  
Stem Height ◽  
Mach Numbers ◽  
Relative Errors ◽  
Cfd Method

The prediction of Mach stem height can be important in the design of supersonic intake in supersonic and hypersonic flows. It is also important because of the progress in aircraft and rocket engines. An analytical method of predicting the Mach stem height is necessary in theoretical field of shock reflection and is the basis of the comparable computational fluid dynamics (CFD) method. A method for predicting the Mach stem height in steady flows is performed based on the earlier models. In this article, an analytical model for predicting the Mach stem height is improved based on two main assumptions: one is the calculation of the triple point deflection angle when the Mach stem is an oblique shock and the other is about the shape of the free part of the slip line. Under these assumptions, the relations predicting of Mach stem height in two-dimensional steady flow are derived based on the advanced averaging method of the subsonic flow region. The Mach stem heights are decided solely for the incoming flow Mach numbers and the wedge angles by the improved analytical model. As a result, the Mach stem heights by the model of this article are found to agree well with experimental results at lower Mach numbers, but there are relative errors at higher Mach numbers. The convexity of the slip line is also considered.

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