The Influence of Shock Reflections on Detonation Re-initiation

Shock reflections over a convex and a concave wedge were investigated by using a 5 × 7 cm ordinary pressure-driven shock tube. Dry air was used for both the driving and driven gases. The large difference between the transition from regular (RR) to Mach reflection (MR) and that from MR to RR was observed, confirming the results obtained by Ben-Dor, Takayama & Kawauchi (1980). These results contradict all of the previous theoretical transition criteria. A new theory on the transition between RR and MR was developed by applying Whitham's ‘ray shock’ theory. This new theory agrees quite well with the experimental results.

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Shock compression of a perfect gas

Journal of Fluid Mechanics ◽

10.1017/s002211205600024x ◽

1956 ◽

Vol 1 (4) ◽

pp. 399-408 ◽

Cited By ~ 11

Author(s):

Cerda Evans ◽

Foster Evans

Keyword(s):

Shock Compression ◽

Entropy Change ◽

Rigid Wall ◽

Adiabatic Process ◽

Perfect Gas ◽

Compression Process ◽

Specific Heats ◽

Initial Shock ◽

The One ◽

Shock Reflections

The compression of a perfect gas between a uniformaly moving piston and a rigid wall is discussed in the one-dimensional case. If the piston moves with a finite speed, it will initiate a shock in the gas which will reflect successively from rigid wall and piston and cause the compression process to deviate from a reversible adiabatic process. Expressions are derived for the relative changes in pressure and density at each shock reflection. Then values of density and pressure after any number of shock reflections are computed relative to their initial values, and, in terms of these, the corresponding values of temperature and entropy, as well as shock speeds, are determined. The limiting value of the entropy change, as the number of reflections goes to infinity, is obtained as a function of the ratio of specific heats of the gas and the strength of the initial shock. Hence it is possible to estimate an upper limit to the deviation of the shock compression process from a reversible adiabatic process. Some illustrative numerical examples are given.

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Computation of weak steady shock reflections by means of an unstructured shock-fitting solver

Shock Waves ◽

10.1007/s00193-010-0266-y ◽

2010 ◽

Vol 20 (4) ◽

pp. 271-284 ◽

Cited By ~ 17

Author(s):

Mikhail S. Ivanov ◽

Aldo Bonfiglioli ◽

Renato Paciorri ◽

Filippo Sabetta

Keyword(s):

Shock Fitting ◽

Shock Reflections ◽

Steady Shock

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Shock-wave reflections over double-concave cylindrical reflectors

Journal of Fluid Mechanics ◽

10.1017/jfm.2016.825 ◽

2017 ◽

Vol 813 ◽

pp. 70-84 ◽

Cited By ~ 11

Author(s):

V. Soni ◽

A. Hadjadj ◽

A. Chaudhuri ◽

G. Ben-Dor

Keyword(s):

Shock Wave ◽

Triple Point ◽

Early Stage ◽

Incident Shock ◽

Incident Shock Wave ◽

Geometrical Parameters ◽

Regular Reflection ◽

Wave Reflections ◽

The Past ◽

Shock Reflections

Numerical simulations were conducted to understand the different wave configurations associated with the shock-wave reflections over double-concave cylindrical surfaces. The reflectors were generated computationally by changing different geometrical parameters, such as the radii of curvature and the initial wedge angles. The incident-shock-wave Mach number was varied such as to cover subsonic, transonic and supersonic regimes of the flows induced by the incident shock. The study revealed a number of interesting wave features starting from the early stage of the shock interaction and transition to transitioned regular reflection (TRR) over the first concave surface, followed by complex shock reflections over the second one. Two new shock bifurcations have been found over the second wedge reflector, depending on the velocity of the additional wave that appears during the TRR over the first wedge reflector. Unlike the first reflector, the transition from a single-triple-point wave configuration (STP) to a double-triple-point wave configuration (DTP) and back occurred several times on the second reflector, indicating that the flow was capable of retaining the memory of the past events over the entire process.

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Numerical Investigation on Axisymmetric and Planar Shock Reflections in Steady Viscous Flow

Proceedings of the 32nd International Symposium on Shock Waves (ISSW32 2019) ◽

10.3850/978-981-11-2730-4_0334-cd ◽

2019 ◽

Author(s):

G. Shoev ◽

H. Ogawa

Keyword(s):

Viscous Flow ◽

Numerical Investigation ◽

Planar Shock ◽

Shock Reflections

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Experimental and Numerical Study of Shock Wave Interaction with Perforated Plates

Journal of Fluids Engineering ◽

10.1115/1.1758264 ◽

2004 ◽

Vol 126 (3) ◽

pp. 399-409 ◽

Cited By ~ 35

Author(s):

A. Britan ◽

A. V. Karpov ◽

E. I. Vasilev ◽

O. Igra ◽

G. Ben-Dor ◽

...

Keyword(s):

Shock Wave ◽

Numerical Study ◽

Wave Interaction ◽

Wave Pattern ◽

Incident Shock ◽

Incident Shock Wave ◽

Navier Stokes ◽

Navier Stokes Equation ◽

Perforated Plates ◽

Shock Reflections

The flow developed behind shock wave transmitted through a screen or a perforated plat is initially highly unsteady and nonuniform. It contains multiple shock reflections and interactions with vortices shed from the open spaces of the barrier. The present paper studies experimentally and theoretically/numerically the flow and wave pattern resulted from the interaction of an incident shock wave with a few different types of barriers, all having the same porosity but different geometries. It is shown that in all investigated cases the flow downstream of the barrier can be divided into two different zones. Due immediately behind the barrier, where the flow is highly unsteady and nonuniform in the other, placed further downstream from the barrier, the flow approaches a steady and uniform state. It is also shown that most of the attenuation experienced by the transmitted shock wave occurs in the zone where the flow is highly unsteady. When solving the flow developed behind the shock wave transmitted through the barrier while ignoring energy losses (i.e., assuming the fluid to be a perfect fluid and therefore employing the Euler equation instead of the Navier-Stokes equation) leads to non-physical results in the unsteady flow zone.

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