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1.
S. P. Kiselev 《Journal of Applied Mechanics and Technical Physics》1998,39(6):842-846
The shock-wave structure in a porous elastoplastic material is studied. In a certain range of parameters, the existence of
a four-wave structure of a compression shock wave is possible. Regimes in which a reflected shock wave does not appear at
all have been found in the problem of shock-wave reflection from a rigid wall. In this case, the entire energy of the incident
shock wave transforms to thermal energy due to dissipation induced by the viscous collapse of the pores.
Institute of Theoretical and Applied Mechanics, Siberian Division, Russian Academy of Sciences, Novosibirsk 630090. Translated
from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, Vol. 39, No. 6, pp. 27–32, November–December, 1998. 相似文献
2.
We calculate the quasi-stationary structure of a radiating shock wave propagating through a spherically symmetric shell of
cold gas by solving the time-dependent equations of radiation hydrodynamics on an implicit adaptive grid. We show that this
code successfully resolves the shock wave in both the subcritical and supercritical cases and, for the first time, we have
reproduced all the expected features – including the optically thin temperature spike at a supercritical shock front – without
invoking analytic jump conditions at the discontinuity. We solve the full moment equations for the radiation flux and energy
density, but the shock wave structure can also be reproduced if the radiation flux is assumed to be proportional to the gradient
of the energy density (the diffusion approximation), as long as the radiation energy density is determined by the appropriate
radiative transfer moment equation. We find that Zel'dovich and Raizer's (1967) analytic solution for the shock wave structure
accurately describes a subcritical shock but it underestimates the gas temperature, pressure, and the radiation flux in the
gas ahead of a supercritical shock. We argue that this discrepancy is a consequence of neglecting terms which are second order
in the minimum inverse shock compression ratio [, where is the adiabatic index] and the inaccurate treatment of radiative transfer near the discontinuity. In addition, we verify
that the maximum temperature of the gas immediately behind the shock is given by , where is the gas temperature far behind the shock.
Received 21 September 1998/ Accepted 2 February 1999 相似文献
3.
Results from an experimental investigation of the interaction of a “non-ideal” shock wave and a single obstacle are reported. The shock wave is produced ahead of an accelerated flame in a 14 cm inner-diameter tube partially filled with orifice plates. The shock wave interacts with a single larger blockage orifice plate placed 15–45 cm after the last orifice plate in the flame acceleration section of the tube. Experiments were performed with stoichiometric ethylene–oxygen mixtures with varying amounts of nitrogen dilution at atmospheric pressure and temperature. The critical nitrogen dilution was found for detonation initiation. It is shown that detonation initiation occurs if the chemical induction time based on the reflected shock state is shorter than the time required for an acoustic wave to traverse the orifice plate upstream surface, from the inner to the outer diameter. The similarity between the present results and those obtained from previous investigators looking at detonation initiation by ideal shock reflection produced in a shock tube indicates that the phenomenon is not sensitive to the detailed structure of the shock front but only on the average shock strength.This paper is based on work that was presented at the 20th International Colloquium on the Dynamics of Explosions and Reactive Systems, Montreal, Canada, July 31–August 5, 2005. 相似文献
4.
We have used a third-order essentially non-oscillatory method to obtain numerical shadowgraphs for investigation of shock–vortex
interaction patterns. To search different interaction patterns, we have tested two vortex models (the composite vortex model
and the Taylor vortex model) and as many as 47 parametric data sets. By shock–vortex interaction, the impinging shock is deformed
to a S-shape with leading and lagging parts of the shock. The vortex flow is locally accelerated by the leading shock and
locally decelerated by the lagging shock, having a severely elongated vortex core with two vertices. When the leading shock
escapes the vortex, implosion effect creates a high pressure in the vertex area where the flow had been most expanded. This
compressed region spreads in time with two frontal waves, an induced expansion wave and an induced compression wave. They
are subsonic waves when the shock–vortex interaction is weak but become supersonic waves for strong interactions. Under a
intermediate interaction, however, an induced shock wave is first developed where flow speed is supersonic but is dissipated
where the incoming flow is subsonic. We have identified three different interaction patterns that depend on the vortex flow
regime characterized by the shock–vortex interaction.
相似文献
5.
V. E. Dontsov 《Journal of Applied Mechanics and Technical Physics》2005,46(3):346-354
Propagation of a stepwise shock wave in a liquid containing spherical gas-liquid clusters is experimentally studied. Measured
results are compared with available theoretical models. It is shown that resonant interaction of gas-liquid clusters in the
wave can increase the amplitude of oscillations in the shock wave.
__________
Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, Vol. 46, No. 3, pp. 50–60, May–June, 2005. 相似文献
6.
V. E. Dontsov V. E. Nakoryakov A. A. Chernov 《Journal of Applied Mechanics and Technical Physics》2007,48(3):346-360
The evolution of a shock wave and its reflection from a wall in a gas-liquid medium with dissolution and hydration are experimentally
investigated. Dissolution and hydration behind the front of a moderate-amplitude shock wave are demonstrated to be caused
by fragmentation of gas bubbles, resulting in a drastic increase in the area of the interphase surface and in a decrease in
size of gas inclusions. The mechanisms of hydration behind the wave front are examined. Hydration behind the front of a shock
wave with a stepwise profile is theoretically analyzed.
__________
Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, Vol. 48, No. 3, pp. 58–75, May–June, 2007. 相似文献
7.
It was recently demonstrated that shock wave enhancement could be achieved when a shock propagates in a constant cross-section
duct through pairs of air–helium layers having a continually decreasing width (Igra and Igra in Shock Waves 16(3):199–207).
A parametric study was conducted aimed at finding a two-layered, light–heavy gas arrangement that yields maximal shock enhancement;
the heavy and the light gases used were air and helium, respectively. Effects associated with changes in following parameters
were investigated: the number of alternating heavy/light gas layers, the applied reduction ratio between successive layers
thickness, and the initial shock wave Mach number.
相似文献
8.
P. N. Baronets 《Fluid Dynamics》1994,29(1):129-132
An experimental investigation of a spark discharge in argon is described. The existence of a shock wave and a following thermal
wave is demonstrated. The experimental law of propagation of the thermal wave front is obtained. The effect of the discharge
parameters on the dynamics of both waves is studied. The interaction between the cylindrical shock waves generated by a pulsed
induction discharge and the shock waves formed in a spark discharge is considered.
Moscow. Translated from Izvestiya Rossiiskoi Akademii Nauk, Mekhanika Zhidkosti i Gaza, No. 1, pp. 166–170, January–February,
1994. 相似文献
9.
V. E. Dontsov 《Journal of Applied Mechanics and Technical Physics》1998,39(5):666-670
The present paper is concerned with an experimental study of the process of gas dissolution behind a shock wave in a liquid
with bubbles of a readily soluble gas, the influence of gas dissolution on the wave evolution, and strengthening of the shock
wave after reflection from a solid wall.
Kutateladze Institute of Thermal Physics, Siberian Division, Russian Academy of Sciences, Novosibirsk 630090. Translated from
Prikladnaya Mekhanika i Tekhnicheskaya Fizika, Vol. 39, No. 5, pp. 19–24, September–October, 1998. 相似文献
10.
The problem of the formation of a “collective” shock wave reflected from a cloud of particles, which was previously observed
in experiment, is considered. A criterion of formation of a reflected shock wave is obtained based on the numerical and analytical
solutions of the problem.
Institute of Theoretical and Applied Mechanics, Siberian Division, Russian Academy of Sciences, Novosibirsk 630090. Translated
from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, Vol. 39, No. 3, pp. 44–51, May–June, 1998. 相似文献
11.
David E. Zeitoun Yves Burtschell Irina A. Graur Mikhail S. Ivanov Alexey N. Kudryavtsev Yevgeny A. Bondar 《Shock Waves》2009,19(4):307-316
Numerical simulations of shock wave propagation in microchannels and microtubes (viscous shock tube problem) have been performed
using three different approaches: the Navier–Stokes equations with the velocity slip and temperature jump boundary conditions,
the statistical Direct Simulation Monte Carlo method for the Boltzmann equation, and the model kinetic Bhatnagar–Gross–Krook
equation with the Shakhov equilibrium distribution function. Effects of flow rarefaction and dissipation are investigated
and the results obtained with different approaches are compared. A parametric study of the problem for different Knudsen numbers
and initial shock strengths is carried out using the Navier–Stokes computations.
相似文献
12.
S. M. Aulchenko V. P. Zamuraev A. P. Kalinina 《Journal of Applied Mechanics and Technical Physics》2006,47(3):359-365
Changes in the structure of a transonic flow around a symmetric airfoil and a decrease in the wave drag of the latter, depending
on the energy-supply period and on localization and shape of the energy-supply zone, are considered by means of the numerical
solution of two-dimensional unsteady equations of gas dynamics. Energy addition to the gas ahead of the closing shock wave
in an immediate vicinity of the contour in zones extended along the contour is found to significantly reduce the wave drag
of the airfoil. The nature of this decrease in drag is clarified. The existence of a limiting frequency of energy supply is
found.
__________
Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, Vol. 47, No. 3, pp. 64–71, May–June, 2006. 相似文献
13.
The breakup of a liquid droplet induced by a high speed gas stream is a typical multiphase flow problem. The shock/droplet
interaction is the beginning stage of the droplet breakup. Therefore, investigation of the shock/droplet interactions would
be a milestone for interpreting the mechanism of the droplet breakup. In this study, a compressible multiphase solver with
a five-equation model is successfully developed to study shock/water column interactions. For code validation, interface-only,
gas–gas shock tube, and gas–liquid shock tube problems are first computed. Subsequently, a planar shock wave interacting with
a water column is simulated. The transmitted wave and the alternative appearances of local high- and low-pressure regions
inside the water column are observed clearly. Finally, a planar shock wave interacting with two water columns is investigated.
In this work, both horizontal and vertical arrangements of two water columns are studied. It is found that different arrangements
can result in the diversity of the interacting process. The complex flow structures generated by shock/water column interactions
are presented by flow-visualization techniques.
相似文献
14.
A new preferential vibration-dissociation-exchange reactions coupling model – labelled CVDEV – resulting from an extension
of the well-known Treanor and Marrone CVDV model, has been derived to take into account the coupling between the vibrational
excitation of the and molecules and the two Zeldovich exchange reactions. Analytical expressions for the exchange reactions coupling factor and
for the average vibrational energy lost – or gained – by a molecule through an exchange reaction have been developed. The
influence of such a coupling has been shown by means of numerical simulations of hypersonic air flows through normal and bow
shock waves. Code-to-code comparisons between our model and other recent approaches have been conducted. The infrared radiation
of nitric oxide behind a normal shock wave resulting from computations with the CVDEV model has been compared with other coupling
model results and to recent shock tube experimental data. These comparisons have shown a good agreement of our model results
with the experimental data. In this context, the results show the prominent influence of vibration coupling on the first Zeldovich reaction, and the absence of vibration coupling effects on the second Zeldovich reaction.
Received 30 June 1997 / Accepted 3 December 1997 相似文献
15.
We study the vanishing viscosity limit of the compressible Navier–Stokes equations to the Riemann solution of the Euler equations
that consists of the superposition of a shock wave and a rarefaction wave. In particular, it is shown that there exists a
family of smooth solutions to the compressible Navier–Stokes equations that converges to the Riemann solution away from the
initial and shock layers at a rate in terms of the viscosity and the heat conductivity coefficients. This gives the first
mathematical justification of this limit for the Navier–Stokes equations to the Riemann solution that contains these two typical
nonlinear hyperbolic waves. 相似文献
16.
H.G. Hornung 《Shock Waves》1998,8(1):11-21
The inviscid equations of motion for the flow at the downstream side of a curved shock are solved for the shock–normal derivatives.
Combining them with the shock–parallel derivatives yields gradients and substantial derivatives. In general these consist
of two terms, one proportional to the rate of removal of specific enthalpy by the reaction, and one proportional to the shock
curvature. Results about the streamline curvature show that, for sufficiently fast exothermic reaction, no Crocco point exists.
This leads to a stability argument for sinusoidally perturbed normal shocks that relates to the formation of the structure
of a detonation wave. Application to the deflection–pressure map of a streamline emerging from a triple shock point leads
to the conclusion that, for non–reacting flow, the curvature of the Mach stem and reflected shock must be zero at the triple
point, if the incident shock is straight. The direction and magnitude of the gradient at the shock of any flow quantity may
be written down using the results. The sonic line slope in reacting flow serves as an example. Extension of the results –
derived in the first place for plane flow – to three dimensions is straightforward.
Received 12 February 1997 / Accepted 10 June 1997 相似文献
17.
This paper discusses gas-dynamic aspects of intense explosions in uniform environments. In experiments, the energy of a laser
is almost instantaneously released in a volume of air shaped as either a flattened or stretched cylinder generating a blast
wave. Its shape evolves in time and ultimately becomes spherical. But momentum transferred to the air when the blast wave
is strongly nonspherical is anisotropic. As a result, a subsonic jet and a vortex are induced and propagate along the symmetry
axis or along the perpendicular plane, depending on the initial configuration of the blast wave. Simulations based on a free-Lagrangian
method for a nonviscous gas are in good agreement with the experiments. Velocities, circulation, and positions of fluid particles
found in computations give an insight into the causes and details of the flow. Two simultaneous and contrary processes take
place – vorticity production by the anisotropic shock wave and baroclinical generation of vorticity at the boundary of the
heated gas – which give rise to net circulation.
Received 21 April 1997 / Accepted 27 June 1997 相似文献
18.
The flow field developed behind a shock wave propagating inside a constant cross-section conduit is solved numerically for
two different cases. First, when the density of the ambient gas into which the shock propagates has a logarithmic change with
distance. In the second, and the more practical case, the ambient gas is composed of pairs of air–helium layers having a continually
decreasing width. It is shown that in both cases meaningful pressure amplification can be reached behind the transmitted shock
wave. It is especially so in the second case. By proper choice of the number of air–helium layers and their width reduction
ratio, pressure amplification as high as 7.5 can be obtained.
相似文献
19.
Head-on Collision of a Detonation with a Planar Shock Wave 总被引:1,自引:0,他引:1
H. D. Ng B. B. Botros J. Chao J. M. Yang N. Nikiforakis J. H. S. Lee 《Shock Waves》2006,15(5):341-352
The phenomenon that occurs when a Chapman–Jouguet (CJ) detonation collides with a shock wave is discussed. Assuming a one-dimensional steady wave configuration analogous to a planar shock–shock frontal interaction, analytical solutions of the Rankine–Hugoniot relationships for the transmitted detonation and the transmitted shock are obtained by matching the pressure and particle velocity at the contact surface. The analytical results indicate that there exist three possible regions of solutions, i.e. the transmitted detonation can have either strong, weak or CJ solution, depending on the incident detonation and shock strengths. On the other hand, if we impose the transmitted detonation to have a CJ solution followed by a rarefaction fan, the boundary conditions are also satisfied at the contact surface. The existence of these multiple solutions is verified by an experimental investigation. It is found that the experimental results agree well with those predicted by the second wave interaction model and that the transmitted detonation is a CJ detonation. Unsteady numerical simulations of the reactive Euler equations with both simple one-step Arrhenius kinetic and chain-branching kinetic models are also carried out to look at the transient phenomena and at the influence of a finite reaction thickness of a detonation wave on the problem of head-on collision with a shock. From all the computational results, a relaxation process consisting of a quasi-steady period and an overshoot for the transmitted detonation subsequent to the head-on collisions can be observed, followed by the asymptotic decay to a CJ detonation as predicted theoretically. For unstable pulsating detonations, it is found that, due to the increase in the thermodynamic state of the reactive mixture caused by the shock, the transmitted pulsating detonation can become more stable with smaller amplitude and period oscillation. These observations are in good agreement with experimental evidence obtained from smoked foils where there is a significant decrease in the detonation cell size after a region of relaxation when the detonation collides head-on with a shock wave. 相似文献
20.
V. E. Dontsov V. E. Nakoryakov 《Journal of Applied Mechanics and Technical Physics》2000,41(5):845-854
The process of evolution and reflection of shock waves of moderate amplitude from a rigid boundary in a porous medium saturated
by a liquid with bubbles of a soluble gas is studied experimentally. Experimental values of the amplitude and velocity of
the reflected wave are compared with the calculated results obtained using mathematical models. The process of dissolution
of gas bubbles in the liquid behind the shock wave is studied.
Kutateladze Institute of Thermal Physics, Siberian Division, Russian Academy of Sciences, Novosibirsk 630090. Translated from
Prikladnaya Mekhanika i Tekhnicheskaya Fizika, Vol. 41, No. 5, pp. 91–102, September–October, 2000. 相似文献