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1.
N. I. Shishkin 《Journal of Applied Mechanics and Technical Physics》2007,48(2):145-152
The seismic energy transferred to an elastic half-space as a result of a contact explosion and a meteorite impact on a planet’s
surface is estimated. The seismic efficiency of the explosion and impact are evaluated as the ratio of the energy of the generated
seismic waves to the energy of explosion or the kinetic energy of the meteorite. In the case of contact explosions, this ratio
is in the range of 10−4–10−3. In the case of wide-scale impact effects, where the crater in the planet’s crust is produced in the gravitational regime,
a formula is derived that relates the seismic efficiency of an impact to its determining parameters.
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Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, Vol. 48, No. 2, pp. 3–12, March–April, 2007. 相似文献
2.
Asterios Pantokratoras 《Transport in Porous Media》2009,80(2):223-227
In this article, we extend the work of Chakrabarti and Gupta (1979, Quart. Appl. Math., Vol. 37, pp. 73–78), and the work
of Pop and Na (1998, Mechanics Research Communications, Vol. 25, pp. 263–269) to a Darcy–Brinkman porous medium. 相似文献
3.
We perform a rigorous analysis of the quasi-neutral limit for a model of viscous plasma represented by the Navier–Stokes–Poisson
system of equations. It is shown that the limit problem is the Navier–Stokes system describing a barotropic fluid flow, with
the pressure augmented by a component related to the nonlinearity in the original Poisson equation. 相似文献
4.
The effects of viscous dissipation on unsteady free convection from an isothermal vertical flat plate in a fluid saturated
porous medium are examined numerically. The Darcy–Brinkman–Forchheimer model is employed to describe the flow field. A new
model of viscous dissipation is used for the Darcy–Brinkman–Forchheimer model of porous media. The simultaneous development
of the momentum and thermal boundary layers are obtained by using a finite difference method. Boundary layer and Boussinesq
approximation have been incorporated. Numerical calculations are carried out for various parameters entering into the problem.
Velocity and temperature profiles as well as local friction factor and local Nusselt number are shown graphically. It is found
that as time approaches infinity, the values of friction factor and heat transfer coefficient approach steady state. 相似文献
5.
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
6.
A. G. Kolpakov 《Journal of Applied Mechanics and Technical Physics》2008,49(5):823-831
The possibility of increasing the control coefficient of a nonlinear dielectric is studied. Composite structures are designed
for which the control coefficient of the composite is considerably (5–20 times) higher than the control coefficients of its components are developed.
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Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, Vol. 49, No. 5, pp. 143–152, September–October, 2008. 相似文献
7.
In the last 30 years, some authors have been studying several classes of boundary value problems (BVP) for partial differential
equations (PDE) using the method of reduction to obtain a difference equation with continuous argument which behavior is determined
by the iteration of a one-dimensional (1D) map (see, for example, Romanenko, E. Yu. and Sharkovsky, A. N., International Journal of Bifurcation and Chaos 9(7), 1999, 1285–1306; Sharkovsky, A. N., International Journal of Bifurcation and Chaos 5(5), 1995, 1419–1425; Sharkovsky, A. N., Analysis Mathematica Sil 13, 1999, 243–255; Sharkovsky, A. N., in “New Progress in Difference Equations”, Proceedings of the ICDEA'2001, Taylor and Francis, 2003, pp. 3–22; Sharkovsky, A. N., Deregel, Ph., and Chua, L. O., International Journal of Bifurcation and Chaos 5(5), 1995, 1283–1302; Sharkovsky, A. N., Maistrenko, Yu. L., and Romanenko, E. Yu., Difference Equations and Their Applications, Kluwer, Dordrecht, 1993.). In this paper we consider the time-delayed Chua's circuit introduced in (Sharkovsky, A. N., International Journal of Bifurcation and Chaos 4(5), 1994, 303–309; Sharkovsky, A. N., Maistrenko, Yu. L., Deregel, Ph., and Chua, L. O., Journal of Circuits, Systems and Computers 3(2), 1993, 645–668.) which behavior is determined by properties of one-dimensional map, see Sharkovsky, A. N., Deregel, Ph.,
and Chua, L. O., International Journal of Bifurcation and Chaos 5(5), 1995, 1283–1302; Maistrenko, Yu. L., Maistrenko, V. L., Vikul, S. I., and Chua, L. O., International Journal of Bifurcation and Chaos 5(3), 1995, 653–671; Sharkovsky, A. N., International Journal of Bifurcation and Chaos 4(5), 1994, 303–309; Sharkovsky, A. N., Maistrenko, Yu. L., Deregel, Ph., and Chua, L. O., Journal of Circuits, Systems and Computers 3(2), 1993, 645–668. To characterize the time-evolution of these circuits we can compute the topological entropy and to distinguish
systems with equal topological entropy we introduce a second topological invariant. 相似文献
8.
A numerical study of mixed convection in a vertical channel filled with a porous medium including the effect of inertial forces
is studied by taking into account the effect of viscous and Darcy dissipations. The flow is modeled using the Brinkman–Forchheimer-extended
Darcy equations. The two boundaries are considered as isothermal–isothermal, isoflux–isothermal and isothermal–isoflux for
the left and right walls of the channel and kept either at equal or at different temperatures. The governing equations are
solved numerically by finite difference method with Southwell–Over–Relaxation technique for extended Darcy model and analytically
using perturbation series method for Darcian model. The velocity and temperature fields are obtained for various porous parameter,
inertia effect, product of Brinkman number and Grashof number and the ratio of Grashof number and Reynolds number for equal
and different wall temperatures. Nusselt number at the walls is also determined for three types of thermal boundary conditions.
The viscous dissipation enhances the flow reversal in the case of downward flow while it counters the flow in the case of
upward flow. The Darcy and inertial drag terms suppress the flow. It is found that analytical and numerical solutions agree
very well for the Darcian model.
An erratum to this article is available at . 相似文献
9.
V. L. Sennitskii 《Journal of Applied Mechanics and Technical Physics》1999,40(4):662-668
A solution is obtained for the problem of the motion of a sphere in an ideal liquid bounded from outside by a wall which performs
specified vibrations far from the sphere.
Lavrent’ev Institute of Hydrodynamics, Siberian Division, Russian Academy of Sciences. Novosibirsk 630090, Translated from
Prikladnaya Mekhanika i Tekhnicheskaya Fizika, Vol. 40, No. 4, pp. 125–132, July–August. 1999. 相似文献
10.
V. G. Chernyak I. V. Chermyaninov E. A. Vilisova E. A. Subbotin 《Journal of Applied Mechanics and Technical Physics》1994,35(5):643-652
Ekaterinburg. Translated from Prikladaya Mekhanika i Tekhnicheskaya Fizika, No. 5, pp. 3–13, September–October, 1994. 相似文献
11.
We investigate the problem of the existence of a Green–Samoilenko function for some linear extensions of dynamical systems.
Translated from Neliniini Kolyvannya, Vol. 12, No. 1, pp. 99–109, January–March, 2009. 相似文献
12.
A. V. Gorin A. V. Zarubin T. N. Mikhailova V. A. Mukhin D. F. Sikovskii 《Journal of Applied Mechanics and Technical Physics》1995,36(1):105-113
Novosibirsk. Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, No. 1, pp. 112–121, January–Feburary, 1995. 相似文献
13.
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
14.
An ablation model for a hydrogen pellet accelerating in a thermonuclear facility fuel-injector bore is developed. The model
is based on the Lagrange internal-ballistic problem complemented by the Stefan conditions on the ablating surface of the pellet
Calculations demonstrate that, during pellet motion in the bore under the action of the gas, the pellet length remains almost
unchanged, while due to the heat exchange with the bore walls the pellet diameter decreases by 4–10%
St. Petersburg. Translated from Izvestiya Rossiiskoi Akademii Nauk, Mekhanika Zhidkosti i Gaza, No. 1, pp. 3–11, January–February,
1999. 相似文献
15.
B. F. Boyarshinov 《Journal of Applied Mechanics and Technical Physics》2000,41(4):686-691
It is shown that, for a certain proportion between the rib height (2–15 mm) installed at the test-section entrance and the turbulence level of the main flow (1–26%), there are extrema of parameters that describe mass transfer on the surface of an evaporating liquid fuel. In tests with
and without combustion, discrete changes in the rates of heat and mass transfer are observed. Conditions for their manifestation
are analyzed.
Kutateladze Institute of Thermal Physics, Siberian Division, Russian Academy of Sciences, Novosibirsk 630090. Translated from
Prikladnaya Mekhanika i Tekhnicheskava Fizika, Vol. 41, No.4, pp. 124–130, July–August, 2000. 相似文献
16.
The axisymmetric problem of the evolution of the free surface of a fluid during the filling of a toroidal vessel under conditions
of weightlessness is considered. Despite its interest [1, 2], this topical problem of the hydrodynamics of weightlessness
remains unsolved for lack of an effective method of solution. This paper employs the iteration-difference approach proposed
in [3–5] for calculating simply and doubly connected axisymmetric equilibrium figures.
Translated from Izvestiya Akademii Nauk SSSR, Mekhanika Zhidkosti i Gaza, No. 6, pp. 154–156, November–December, 1986. 相似文献
17.
V. P. Kiselev S. P. Kiselev V. M. Fomin 《Journal of Applied Mechanics and Technical Physics》1994,35(2):183-192
Novosibirsk. Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, No. 2, pp. 26–37, March–April, 1994. 相似文献
18.
Quan Chen 《Rheologica Acta》2012,51(4):343-355
Cyclic block copolymer is a special type of block copolymer having no free ends. Comparison of the dynamic behavior between
cyclic and linear block copolymers enables an understanding of the role of chain ends in dynamics of the latter. In relation
to this point, analysis was made on the conformational dynamics for a cyclic bead-spring type diblock copolymer chain, AoB,
under the steady shear flow. Further comparison was made on the conformational behavior of the AoB chain and that of two symmetric
linear triblock copolymer chains, A–B–A and B–A–B. For these chains, the mobility was set to be higher for the A segments
than the B segments. Thus, for the AoB chain under the steady shear flow, the segments of the A block exhibit less orientational
anisotropy than those of the B block. This orientational contrast is enhanced for the A–B–A chain partly because the constraint
for the motion of the segments is less near the chain ends than near the chain center. Nevertheless, for the B–A–B chain,
the segmental orientation over the A block becomes more anisotropic than that over the B block. Detailed analysis shows that
this result is attributable to a high orientational correlation for the segments of two end B blocks, in particularly for
those near the block junctions. The correlated B segments exert a tensile force on the A block thereby significantly enhancing
the orientational anisotropy of the A segments. 相似文献
19.
Prediction of separation flows around a 6:1 prolate spheroid using RANS/LES hybrid approaches 总被引:2,自引:0,他引:2
Zhixiang Xiao Yufei Zhang Jingbo Huang Haixin Chen Song Fu 《Acta Mechanica Sinica》2007,23(4):369-382
This paper presents hybrid Reynolds-averaged Navier–Stokes (RANS) and large-eddy-simulation (LES) methods for the separated
flows at high angles of attack around a 6:1 prolate spheroid. The RANS/LES hybrid methods studied in this work include the
detached eddy simulation (DES) based on Spalart–Allmaras (S–A), Menter’s k–ω shear-stress-transport (SST) and k–ω with weakly nonlinear eddy viscosity formulation (Wilcox–Durbin+, WD+) models and the zonal-RANS/LES methods based on the
SST and WD+ models. The switch from RANS near the wall to LES in the core flow region is smooth through the implementation
of a flow-dependent blending function for the zonal hybrid method. All the hybrid methods are designed to have a RANS mode
for the attached flows and have a LES behavior for the separated flows. The main objective of this paper is to apply the hybrid
methods for the high Reynolds number separated flows around prolate spheroid at high-incidences. A fourth-order central scheme
with fourth-order artificial viscosity is applied for spatial differencing. The fully implicit lower–upper symmetric-Gauss–Seidel
with pseudo time sub-iteration is taken as the temporal differentiation. Comparisons with available measurements are carried
out for pressure distribution, skin friction, and profiles of velocity, etc. Reasonable agreement with the experiments, accounting
for the effect on grids and fundamental turbulence models, is obtained for the separation flows.
The project supported by the National Natural Science Foundation of China (10502030 and 90505005). 相似文献
20.
E. V. Proskuryakov M. V. Sorokin V. M. Fomin 《Journal of Applied Mechanics and Technical Physics》2008,49(5):723-724
Coaxial interaction of a copper shaped-charge jet with a thin tungsten rod is considered. A theoretical model of spraying
of the shaped-charge jet on the rod and results of experiments performed are presented.
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Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, Vol. 49, No. 5, pp. 24–26, September–October, 2008. 相似文献