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1.
P. Kosinski 《Shock Waves》2006,15(1):13-20
The problem of wave propagation in a dust–air mixture inside a branched channel has not been studied widely in literature, even though this topic has many important applications especially in process safety (dust explosions). In this paper, a shock wave interaction with a cloud of solid particles, and the further behaviour of both gas and particulate phases were studied using numerical techniques. The geometry mimicked a real channel where bends or branches are common. Two numerical approaches were used: Eulerian–Eulerian and Eulerian–Lagrangian. Using Eulerian-Lagrangian simulation, it was possible to include the effects of particle–particle and particle–wall collisions in a realistic and direct manner. Results are mainly shown as snap-shots of particle positions during the simulations and statistics for the particle displacement. The results show that collisions significantly influence the process of particle cloud formation.
PACS47.40.Nm, 02.60.Cb, 47.55.kf 相似文献
2.
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.
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Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, Vol. 46, No. 3, pp. 50–60, May–June, 2005. 相似文献
3.
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
4.
Shallow water waves and a host of long wave phenomena are commonly investigated by various models of nonlinear evolution equations.
Examples include the Korteweg–de Vries, the Camassa–Holm, and the Whitham–Broer–Kaup (WBK) equations. Here a generalized WBK
system is studied via the multi-linear variable separation approach. A special class of wave profiles with discontinuous derivatives
(“peakons”) is developed. Peakons of various features, e.g. periodic, pulsating or fractal, are investigated and interactions
of such entities are studied.
The project supported by the National Natural Science Foundation of China (10475055, 10547124 and 90503006), and the Hong
Kong Research Grant Council Contract HKU 7123/05E. 相似文献
5.
Victor N. Nikolaevskiy 《Transport in Porous Media》2008,73(2):125-140
The Frenkel–Biot P-wave of the first type is a seismic longitudinal wave observed in rocks fully saturated with oil, water
or high-pressure gas. The P-wave of the second type is observed in unsaturated soils and other porous media saturated with
gas of low pressure. Their models include properties of the skeleton, that is, its elastic modules and its own viscosity.
If the non-linear terms are accounted for, the asymptotic analysis, usual for weak non-linear waves, might be applied to get
the wave spectrum evolution. The wetness of grains contacts in soils and such components of oil as tars or bitumen, which
attached to the skeleton, can be described by generalized viscous–elastic stress–strain connections. The latter are nominated
in such a way that creates the narrow frequency interval of wave of negative dissipation where the non-linear terms begin
to play the main role besides the neutral stability for waves of zero wave number. The corresponding case, relevant to single
continuum model, was analyzed in the literature. Here it is shown that the interpenetrating continua with interaction of the
Darcy type provide the dissipation sink in the wave evolution equation. This generalization, (Tribelsky, M.I.: Phys. Rev.
Lett. (2007, submitted)), can stabilize the asymptotic solution of the evolution equation, where the dispersion terms are
omitted. The asymptotic solution of the equation is invariant to initial conditions and it means a transformation of initial
wave spectra to unique one while wave is spreading in the viscous–elastic medium under consideration. This explains the phenomenon,
observed in wave tests at marine beach, when any dynamics action (impact, explosion, and ultrasound action) created at some
distance a wave of a single frequency (~25 Hz). 相似文献
6.
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
7.
It is shown that a fracture in an elastic plate floating on the surface of a shallow liquid layer is a waveguide along which
wave energy can be transported. The edge wave velocity is less than the velocity of flexural-gravity waves. The existence
of an antisymmetric edge wave mode depends on the Poisson's ratio of the elastic plate.
Moscow. Translated from Izvestiya Rossiiskoi Akademii Nauk, Mekhanika Zhidkosti i Gaza, No. 4, pp. 185–189, July–August, 1994. 相似文献
8.
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.
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Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, Vol. 48, No. 3, pp. 58–75, May–June, 2007. 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.
S. P. Bautin 《Journal of Applied Mechanics and Technical Physics》2009,50(4):576-583
The Kuropatenko model for a multicomponent medium whose components are polytropic gases is considered. It is assumed that,
as x → ±∞, the multicomponent medium is in a homogeneous state with constant gas-dynamic parameters — velocity, pressure,
and temperature. For the traveling wave flows, conditions similar to the Hugoniot conditions are obtained and used to uniquely
determine the flow parameters for x → −∞ from the flow parameters x → +∞ and traveling wave velocity.
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Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, Vol. 50, No. 4, pp. 39–47, July–August, 2009. 相似文献
11.
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
12.
The two-dimensional nonlinear problem of steady gravity waves on water of finite depth is considered. The Benjamin–Lighthill
conjecture is proved for these waves provided Bernoulli’s constant attains near-critical values. In fact this is a consequence
of the following more general results. If Bernoulli’s constant is near-critical, then all corresponding waves have sufficiently
small heights and slopes. Moreover, for every near-critical value of Bernoulli’s constant, there exist only the following
waves: a solitary wave and the family of Stokes waves having their crests strictly below the crest of this solitary wave;
this family is parametrised by wave heights which increase from zero to the height of the solitary wave. All these waves are
unique up to horizontal translations. Most of these results were proved in our previous paper (Kozlov and Kuznetsov in Arch
Rational Mech Anal 197, 433–488, 2010), in which it was supposed that wave slopes are bounded a priori. Here we show that the latter condition is superfluous by
proving the following theorem. If any steady wave has the free-surface profile of a sufficiently small height, then the slope
of this wave is also small. 相似文献
13.
N.A. Adams 《Theoretical and Computational Fluid Dynamics》1998,12(2):109-129
A numerical procedure for the direct numerical simulation of compressible turbulent flow and shock–turbulence interaction
is detailed and analyzed. An upwind-biased finite-difference scheme with a compact centered stencil is used to discretize
the convective part of the Navier–Stokes equations. The scheme has a uniformly high approximation order and allows for a spectral-like
wave resolution while dissipating nonresolved wave numbers. When hybridized with an essentially nonoscillatory scheme near
discontinuities, the scheme becomes shock–capturing and its resolution properties are preserved. Diffusive parts are discretized
with symmetric compact finite differences and an explicit Runge–Kutta scheme is used for time-advancement. The peculiarities
of efficient upwinding and coupling procedures are described and validation results are given. Using direct numerical simulation
data, some aspects of turbulent supersonic compression ramp flow are studied to demonstrate the effectiveness of the simulation
procedure.
Received 13 November 1997 and accepted 14 May 1998 相似文献
14.
In recent years two nonlinear dispersive partial differential equations have attracted much attention due to their integrable
structure. We prove that both equations arise in the modeling of the propagation of shallow water waves over a flat bed. The
equations capture stronger nonlinear effects than the classical nonlinear dispersive Benjamin–Bona–Mahoney and Korteweg–de
Vries equations. In particular, they accommodate wave breaking phenomena. 相似文献
15.
M. D. Anokhin Yu. A. Vinogradov A. I. Zubkov B. E. Lyagushin Yu. A. Panov 《Fluid Dynamics》1998,33(2):186-189
The three-dimensional shape of the shock wave formed ahead of a sonic jet flowing out into a supersonic flow through the surface
of a sharp cone is determined. The shape of the wave in the longitudinal and transverse cross-sections of the model is constructed
using schlieren photographs taken for various angles of rotation and freestream Mach numbers M=1.75–3.
Moscow. Translated from Izvestiya Rossiiskoi Akademii Nauk, Mekhanika Zhidkosti i Gaza, No. 2, pp. 41–44, March–April, 1998.
This research was carried out with financial support from the Russian Foundation for Basic Research (project No. 95-01-00709a). 相似文献
16.
The effect of initial pressure on aluminum particles–air detonation was experimentally investigated in a 13 m long, 80 mm diameter tube for 100 nm and 2 μm spherical particles. While the 100 nm Al–air detonation propagates at 1 atm initial pressure in the tube, transition to the 2 μm aluminum–air detonation occurs only when the initial pressure is increased to 2.5 atm. The detonation wave manifests itself in a spinning wave structure. An increase in initial pressure increases the detonation sensitivity and reduces the detonation transition distance. Global analysis suggests that the tube diameter for single-head spinning detonation or characteristic detonation cell size would be proportional to (d
0: aluminum particle size, p
0: initial pressure). Its application to the experimental data results in m ~ O(1) and n ~ O(1) for 1 to 2 μm aluminum–air detonation, thus indicating a strong dependence on initial pressure and gas-phase kinetics for the aluminum reaction mechanism in detonation. Hence, combustion models based on the fuel droplet diffusion theory may not be adequate in describing micrometric aluminum–air detonation initiation, transition and propagation. For 2 μm aluminum–air mixtures at 2 atm initial pressure and below, experiments show a transition to a “dust quasi-detonation” that propagates quasi-steadily with a shock velocity deficit nearly 40% with respect to the theoretical C–J detonation value. The dust quasi- detonation wave can propagate in a tube with a diameter less than 0.4–0.5 times the diameter required for a spinning detonation wave. 相似文献
17.
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
18.
V. Yu. Liapidevskii 《Journal of Applied Mechanics and Technical Physics》1999,40(2):238-248
A mathematical model for the propagation of nonlinear long waves is constructed with allowance for nonhydrostatic pressure
distribution and the development of a surface boundary layer due to wave breaking. The problem of the structure of a bore
in a homogeneous liquid is solved. In particular, the transition of a wave bore to a turbulent bore as its amplitude increases
is described within a single model.
Lavrent’ev Institute of Hydrodynamics, Siberian Division, Russian Academy of Sciences, Novosibirsk 630090. Translated from
Prikladnaya Mekhanika i Tekhnicheskaya Fizika, Vol. 40, No. 2, pp. 56–68, March–April, 1999. 相似文献
19.
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
20.
A. E. Dubinov 《Journal of Applied Mechanics and Technical Physics》2007,48(5):621-628
An exact solution of the problem of the acoustic wave structure in a plasma is obtained. Both plasma component are treated
as gases with specified initial temperatures and adiabatic exponents. The system of equations describing the wave profile
is solved using an original method consisting of reducing the system to the Bernoulli equation. A numerical example of the
obtained general solution of the problem of the wave profile for arbitrary parameters is given. Curves are constructed that
bound the region of existence of a stationary solitary ion acoustic wave in the parameter space.
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Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, Vol. 48, No. 5, pp. 3–11, September–October, 2007. 相似文献