scholarly journals Coronal Shock Waves, EUV Waves, and Their Relation to CMEs. II. Modeling MHD Shock Wave Propagation Along the Solar Surface, Using Nonlinear Geometrical Acoustics

2011 ◽  
pp. 173-185
Author(s):  
A. N. Afanasyev ◽  
A. M. Uralov
Keyword(s):  
Shock Wave ◽  
Wave Propagation ◽  
Shock Waves ◽  
Solar Surface ◽  
Shock Wave Propagation ◽  
Coronal Shock ◽  
Geometrical Acoustics

Investigation of features of shock wave distribution in the rock massif at gas dynamic phenomena

2020 ◽  
pp. 234-243
Author(s):  
S.I. Skipochka ◽  
◽  
T.A. Palamarchuk ◽  
L.V. Prokhorets ◽  
V.P. Kurinnyi ◽  
...  
Keyword(s):  
Shock Wave ◽  
Wave Propagation ◽  
Shock Waves ◽  
Shock Wave Propagation ◽  
Rock Massif ◽  
Mining Operations ◽  
Technological Factors ◽  
Gas Dynamic ◽  
Methane Mixture ◽  
Dynamic Phenomena

When studying risk factors in coal mines, it is necessary, in the first place, to consider factors and properties of the rock massif occurred with the deepening of mining operations in the coal mines, and determine one of the main types of danger: risk of geodynamic phenomena. The geodynamic phenomena occur and develop under the influence of natural and technological factors. Natural factors determine the rock massif proneness of ato geodynamic manifestations or, in other words, its potential danger due to these phenomena. Occurrence of this danger depends on technological factors. Among the dangerous factors of underground coal production to which primarily belong the geodynamic phenomena, the main ones are gas-dynamic phenomena, which are the most complex by their nature and dangerous by consequences due to high dynamic power and release of great amount of gas during a short period of time. Their consequences can be accidents due to sudden gassing and blockage of workings by coal and rock, explosions of methane and coal dust, destruction of the roadway supports, damage of machines and mechanisms, equipment and devices. As the gas-dynamic phenomena in the rocks massif are accompanied by occurrence of various processes differed by their nature, therefore, risks caused by them should be taken into account at mining operations. When considering the gas-dynamic phenomena attention should be paid to the shock wave propagation, as it is one of the gas dynamic processes. Therefore, purpose of this research was to study specific features of the shock wave propagation in the rock massif in order to prevent dangerous consequences. In this article, the authors consider the processes which occur in the rock massif prone to dangerous gas-dynamic phenomena at the shock wave propagation. The methods of rock mechanics, mechanics of continuous media, gas and thermodynamics were used in the research. Analytical researches of processes and numerical analysis of the received results were carried out. It is shown that a sharp increase of thermodynamic parameters under the action of gas-dynamic phenomena can lead to occurrence of the shock waves. It is further established that an explosive air-methane mixture can be formed in cracks, cavities and pores of the face area. At opening the cavities and pores, cases of shock waves formation in air-methane mixture leading to its detonation are possible. Under adverse conditions, this phenomenon can lead to a fire in the roadway.

Shock-wave induced instability in internal explosion dynamics

2005 ◽  
Vol 109 (1101) ◽  
pp. 537-556 ◽  
Author(s):  
A. Bagabir ◽  
D. Drikakis
Keyword(s):  
Shock Wave ◽  
Wave Propagation ◽  
Shock Waves ◽  
Symmetry Breaking ◽  
Flow Instability ◽  
Shock Wave Propagation ◽  
Vortical Flow ◽  
Density Region ◽  
Riemann Solvers ◽  
Wave Induced

Abstract The paper presents an investigation of flow instabilities occurring in shock-wave propagation and interaction with the walls of an enclosure. The shock-wave propagation is studied in connection with perturbed and unperturbed cylindrical blasts, initially placed in the centre of the enclosure, as well as for three different blast intensities corresponding to Mach numbers Ms = 2, 5 and 10. The instability is manifested by a symmetry-breaking of the flow even for the case of an initially perfectly-symmetric blast. It is shown that the symmetry-breaking initiates around the centre of the enclosure as a result of the interaction of the shock waves reflected from the walls, with the low-density region in the centre of the explosion. The instability leads to fast attenuation of the shock waves, especially for smaller initial blast intensities. The computations reveal that the vortical flow structures arising from the multiple shock reflections and flow instability are Mach number dependent. The existence of perturbations of large amplitude in the initial condition strengthens the instability and has significant effects on the instantaneous wall pressure distributions. The computational investigation has been performed using high-resolution Riemann solvers for the gas dynamic equations.

Propagation of Weak Shock Waves in a Vibrational Nonequilibrium, Nonuniform Gas

1975 ◽  
Vol 42 (3) ◽  
pp. 564-568 ◽  
Author(s):  
D. C. Chou ◽  
S. Y. Maa
Keyword(s):  
Shock Wave ◽  
Wave Propagation ◽  
Shock Waves ◽  
Vibrational Energy ◽  
Weak Shock ◽  
Present Theory ◽  
Shock Wave Propagation ◽  
Perturbation Scheme ◽  
Relaxation Rates ◽  
Vibrational Nonequilibrium

Problems concerned with the propagation of weak planar shock waves in a nonuniform, nonequilibrium gas is theoretically investigated. The medium under consideration is a diatomic thermally perfect gas with excited vibrational energy and is initially inhomogeneous with exponential density and temperature distributions. The systematic characteristic perturbation scheme is employed to render a first-order frozen shock expression. It is shown quantitatively that combined effects of nonequilibrium, nonlinearity, and stratification govern the nature of the shock wave propagation. The uniform gas limit of present theory agrees with previously known results of shock wave propagation in a general relaxing fluid. Numerical examples illustrate the variation of frozen shock strength and speed due to different magnitudes of relaxation rates and inhomogeneity. The interesting competition phenomenon between nonequilibrium effects and nonuniform effects on shock wave propagation is examined.

Optical Diagnostics for Energetic Materials Research

2016 ◽  
Author(s):  
Michael J. Hargather ◽  
Joshua L. Smith ◽  
James Anderson ◽  
Kyle Winter
Keyword(s):  
Shock Wave ◽  
Wave Propagation ◽  
Shock Waves ◽  
High Speed ◽  
Optical Diagnostics ◽  
Shock Wave Propagation ◽  
Field Scale ◽  
Schlieren Imaging ◽  
Image Field ◽  
Explosive Events

Optical diagnostics including schlieren, shadowgraphy, and background-oriented schlieren (BOS) are used to visualize shock waves and compressible flow phenomena present in energetic and explosive events. These techniques visualize refractive index variations to obtain a range of qualitative and quantitative information. A one-dimensional explosively-driven shock tube facility is used with schlieren imaging to measure shock wave propagation speeds from explosive-thermite mixtures. The schlieren imaging visualizes turbulent flow structures in the expanding product gas region. An imaging spectrometer is paired with the schlieren imaging to quantify the mixing of the explosive product gases with the ambient environment. Shadowgraphy is applied to image field-scale explosive tests. The shadowgraph images reveal shock waves, fragment motion and speed, and the motion of product gases. BOS is a modern technique for visualizing refractive fields via their distortion of a background pattern. Here the technique is applied to image field-scale explosive events using the ambient background of the test pad. The BOS images clearly show shock wave propagation and reflection from surfaces, which is not clearly visible in the raw high-speed digital images.

Phenomenological analysis of shock-wave propagation in weakly ionized plasmas

AIAA Journal ◽  
1998 ◽  
Vol 36 ◽  
pp. 816-822
Author(s):  
Igor V. Adamovich ◽  
Vish V. Subramaniam ◽  
J. W. Rich ◽  
Sergey O. Macheret
Keyword(s):  
Shock Wave ◽  
Wave Propagation ◽  
Phenomenological Analysis ◽  
Shock Wave Propagation ◽  
Ionized Plasmas ◽  
Weakly Ionized

scholarly journals Observation of the shock wave propagation induced by a high-power laser irradiation into an epoxy material

2013 ◽  
Vol 46 (23) ◽  
pp. 235501 ◽  
Author(s):  
Romain Ecault ◽  
Laurent Berthe ◽  
Michel Boustie ◽  
Fabienne Touchard ◽  
Emilien Lescoute ◽  
...  
Keyword(s):  
Shock Wave ◽  
Wave Propagation ◽  
Laser Irradiation ◽  
High Power ◽  
Shock Wave Propagation ◽  
High Power Laser ◽  
Power Laser ◽  
Epoxy Material

scholarly journals Universal shock-wave propagation in one-dimensional Bose fluids

2021 ◽  
Vol 3 (1) ◽  
Author(s):  
Romain Dubessy ◽  
Juan Polo ◽  
Hélène Perrin ◽  
Anna Minguzzi ◽  
Maxim Olshanii
Keyword(s):  
Shock Wave ◽  
Wave Propagation ◽  
Shock Wave Propagation ◽  
One Dimensional
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