共查询到20条相似文献,搜索用时 31 毫秒
1.
A. V. Gusev V. V. Ostapenko A. A. Malysheva I. A. Malysheva 《Journal of Applied Mechanics and Technical Physics》2008,49(1):23-33
This paper presents the results of theoretical and experimental studies of open-channel waves generated by the propagation
of a discontinuous dam-break wave over a bottom step. The cases where the initial tailwater level is higher than the step
height (the step is under water) and where this value is smaller than the step height (at the initial time, water is absent
on the step) are considered. Exact solutions are constructed using modified first-approximation equations of shallow-water
theory, which admit the propagation of discontinuous waves in a dry channel. On the stationary hydraulic jump formed above
the bottom step, the total free-stream energy is assumed to be conserved. These solutions agree with experimental data on
various parameters (types of waves, wave propagation velocity, asymptotic depths behind the wave fronts).
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Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, Vol. 49, No. 1, pp. 31–44, January–February, 2008. 相似文献
2.
V. V. Mykhas’kiv N. D. Grilitskii I. O. Butrak 《Journal of Applied Mechanics and Technical Physics》2006,47(4):556-563
A three-dimensional wave field formed owing to diffraction of low-frequency waves on a curved crack in an infinite elastic
solid at a large distance from the defect is studied by the method of boundary integral equations. Direction diagrams of the
scattered field versus the excentricity of the crack surface and wavenumber are obtained for different directions of incidence
of planar longitudinal waves onto a gently sloping spheroidal crack.
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Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, Vol. 47, No. 4, pp. 115–123, July–August, 2006. 相似文献
3.
V. V. Bulatov Yu. V. Vladimirov 《Journal of Applied Mechanics and Technical Physics》2008,49(5):762-769
The field of internal gravity waves in a layer of an arbitrary stratified fluid is studied for critical generation modes and
in the vicinity of trajectories of motion of the perturbation sources. The exact solutions describing the structure of a separate
mode of the wave field in the vicinity of the perturbation source in the critical generation modes are investigated, and expressions
for the total field representing the sum of all wave modes are obtained. In the vicinity of the trajectories of the perturbation
sources, asymptotic representations of the eigenfunctions and eigenvalues of the basic vertical spectral problem of internal
waves are constructed in the approximation of large wave numbers and asymptotic expressions for a separate mode of the wave
field are obtained that describe the spatial structure and features of the fields of internal gravity waves.
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Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, Vol. 49, No. 5, pp. 70–79, September–October, 2008. 相似文献
4.
Homogeneous heavy fluid flows over an uneven bottom are studied in a long-wave approximation. A mathematical model is proposed
that takes into account both the dispersion effects and the formation of a turbulent upper layer due to the breaking of surface
gravity waves. The asymptotic behavior of nonlinear perturbations at the wave front is studied, and the conditions of transition
from smooth flows to breaking waves are obtained for steady-state supercritical flow over a local obstacle.
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Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, Vol. 47, No. 3, pp. 3–11, May–June, 2006. 相似文献
5.
T. V. Bazhenova T. A. Bormotova V. V. Golub A. M. Shul’meister C. B. Shcherbak 《Fluid Dynamics》2000,35(1):117-122
The results of an experimental and numerical investigation of the process of diffraction of shock waves from a square channel
at a ninety-degree convex corner are presented for various incident shock wave Mach numbers M0 (1.4<M0<7). The type of reflection of the near-wall fragment of the diffracting shock wave from the wall and the wave velocity are
determined as functions of M0, direction, and time.
Moscow. Translated from Izvestiya Rossiiskoi Akademii Nauk, Mekhanika Zhidkosti i Gaza, No. 1, pp. 145–151, January–February,
2000.
The work was carried out with partial support from the Russian Foundation for Basic Research (project No. 96-02-16170a). 相似文献
6.
The influence of drifting broken ice on the propagation of small-amplitude plane surface waves from an infinitely deep region
of a basin to a region of finite depth over a bottom shelf is analyzed on the basis of wave source theory. The variations
in the characteristics of the reflected and transmitted waves and the fluid surface perturbation profile due to the drifting
ice are estimated as functions of the distance from the shelf.
Sevastopol. Translated from Izvestiya Rossiiskoi Akademii Nauk, Mekhanika Zhidkosti i Gaza, No. 6, pp. 106–115, November–December,
1998. 相似文献
7.
The dynamics of internal waves of small but finite amplitude in a two-layer fluid system bounded by rigid horizontal surfaces
at bottom and top is investigated theoretically. For linear disturbances of the fluid interface the authors propose a polynomial
approximation of the dispersion relation which has the same asymptotics as the exact formula in the limiting situations of
very long and short waves. In the case of three-dimensional, weakly nonlinear disturbances of slowly varying shape (in the
coordinate system moving with the wave) an equation like the wave equation is derived. This equation has Stokes solutions
coinciding with the well-known results for infinitely deep layers. For fairly long disturbances solitary solutions of the
model wave equation which fit the experimental data are determined.
Novosibirsk. Translated from Izvestiya Rossiiskoi Akademii Nauk, Mekhanika Zhidkosti i Gaza, No.1, pp. 125–131, January–February,
1994. 相似文献
8.
A. V. Pinaev V. T. Kuzavov V. K. Kedrinskii 《Journal of Applied Mechanics and Technical Physics》2000,41(5):836-844
Profiles and values of pressure in shock waves are determined for the case of spherical, linear, and spatial charges, such
as a coil of a bulk spiral and plane annular coils and Archimedes’ spiral of various lenths, exploded in air. In the case
of explosion of rings and spirals, a complex wave structure in the form of a sequence of several shock waves is registered
near the charges along the spiral axes; a weaker attenuation of shock waves with distance and pressure amplitudes two to three
times higher than in the case of a spherical charge of the same mass are observed. It was found that an increase in the length
of a plane spiral does not lead to an increase in the maximum pressure in the shock wave at distances of the order of several
pitches of the spiral from its plane. With distance from spatial charges of different shape but identical mass, the pressure
values in the shock-wave fronts coincide and tend asymptotically to the parameters of a spherical explosion with a significant
increase in the duration of a wave packet generated by the spatial charge. Dependences for evaluation of shock-wave pressure
amplitudes in the near zone of the explosion are presented.
Lavrent’ev Institute of Hydrodynamics, Siberian Division, Russian Academy of Sciences, Novosibirsk 630090. Translated from
Prikladnaya Mekhanika i Tekhnicheskaya Fizika, Vol. 41, No. 5, pp. 81–90, September–October, 2000. 相似文献
9.
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
10.
M. S. Ruderman 《Fluid Dynamics》1986,21(6):925-934
It is proposed to consider the propagation of surface waves along a tangential magnetohydrodynamic discontinuity in the particular
case where the fluid velocities on both sides of the interface are equal to zero. In [1] it was shown that waves called surface
Alfvén waves may be propagated along the surface separating a semi-infinite region without a field from a region with a uniform
magnetic field. The linear theory of surface Alfvén waves in a compressible medium was considered in [2]. In [3] the damping
of surface Alfvén waves as a result of viscosity and heat conduction was investigated. The propagation of low-amplitude nonlinear
surface Alfvén waves in an incompressible fluid in the absence of dissipative processes is described by the integrodifferential
equation obtained in [4]. By means of a numerical solution of this equation it was shown that a perturbation initially in
the form of a sinusoidal wave will break. The breaking time was determined. In this paper the equation derived in [4] is extended
to the case of a viscous fluid. It is shown that the equation obtained does not have steady-state solutions. The propagation
of periodic disturbances is investigated numerically.
Translated from Izvestiya Akademii Nauk SSSR, Mekhanika Zhidkosti i Gaza, No. 6, pp. 94–104, November–December, 1986.
The author wishes to thank L. S. Fedorov for assisting with the calculations. 相似文献
11.
N. V. Gavrilov E. V. Ermanyuk 《Journal of Applied Mechanics and Technical Physics》1999,40(2):258-262
Propagation of internal waves over a circular cylinder under the conditions of a continuous stratification characterized by
the presence of a high-gradient density layer (the pycnocline) of finite thickness is studied. The dependences of the coefficent
of wave propagation on the wavelength of the first-mode incident wave for various thicknesses of the pycnocline are obtained.
In the diffraction of internal waves, substantial nonlinear effects are shown to occur, which result in the appearance of
waves of double oscillation frequency compared to the frequency of the incident waves. The generation coefficient for these
waves is found.
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. 79–85, March–April, 1999. 相似文献
12.
The paper is devoted to the solution of the steady problem of ideal incompressible fluid flow over a semi-circular cylinder
located at the bottom. Calculations showed that the problem has at least three solutions for the Froude number. In the absence
of an obstruction at the bottom, the proposed algorithm allows one to construct solitary waves up to limiting waves. The paper
reports the most important wave characteristics: circulation, mass, and potential and kinetic energy. Analysis of the calculation
results leads to the conclusion that all maximum values of the solitary-wave characteristics are attained before the maximum
amplitude and the maximum of the mass does not coincide with the maxima of the total energy and the Froude number.
Kemerovo State University, Kemerovo 650043. Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, Vol. 40, No. 1,
pp. 27–35, January–February, 1999. 相似文献
13.
A linearized equation of the internal waves developing in an ideal stratified gas under the action of potential vortices concentrated
in a vertical cylinder is obtained. The Cauchy problem for the internal wave equation with right side depending on the vortex
intensity is solved by the integral transform method. In the case of a vortex filament the exact solution is found. Approximate
formulas are obtained on the basis of the steady-phase method when the vorticity is exponentially stratified along the vertical.
Expressions for the phase velocity and amplitude of the radial wave traveling away from the cylindrical vortex are found.
Moscow. Translated from Izvestiya Rossiiskoi Akademii Nauk, Mekhanika Zhidkosti i Gaza, No. 1, pp. 118–123, January–February,
1998.
The work was carried out with the support of the Russian Foundation for Fundamental Research (project No. 96-01-04599). 相似文献
14.
Feimin Huang Jing Li Akitaka Matsumura 《Archive for Rational Mechanics and Analysis》2010,197(1):89-116
We are concerned with the large-time behavior of solutions of the Cauchy problem to the one-dimensional compressible Navier–Stokes
system for ideal polytropic fluids, where the far field states are prescribed. When the corresponding Riemann problem for
the compressible Euler system admits the solution consisting of contact discontinuity and rarefaction waves, it is proved
that for the one-dimensional compressible Navier–Stokes system, the combination wave of a “viscous contact wave”, which corresponds
to the contact discontinuity, with rarefaction waves is asymptotically stable, provided the strength of the combination wave
is suitably small. This result is proved by using elementary energy methods. 相似文献
15.
The results of a theoretical and experimental investigation of the phase structure of three-dimensional internal waves in a horizontal channel occupied by an exponentially stratified fluid are presented. The stationary internal waves excited by a source moving uniformly along the bottom of a channel with rigid covers are considered. A dispersion relation, on the basis of which the phase structure of the internal waves in the far zone is investigated, is obtained within the context of the linear theory. The dependence of the boundary of the region of wave disturbances on the internal Froude number F is found. The equation of the lines of constant phase is obtained in the first approximation for large F. By means of an IAB-451 shadowgraph instrument, using the dark field method with vertical illumination, the phase patterns of the internal waves are obtained. The angles of the wave disturbance zone are measured in the region of relatively large F. Similarity of the phase patterns for the first three-dimensional mode is obtained experimentally for large F.Translated from Izvestiya Akademii Nauk SSSR, Mekhanika Zhidkosti i Gaza, No. 1, pp. 129–135, January–February, 1989.The authors wish to thank A. T. Onufriev for his interest in their work. 相似文献
16.
The structure and characteristics of nonlinear steady waves on the surface of horizontal shear flow of an ideal homogeneous
incompressible fluid of finite depth with a linear velocity profile are studied using two-dimensional theory and the Euler
approach. The wave motion is considered irrotational. A modification of the first Stokes method is proposed that allows algebraic
calculations of terms of perturbation series. Nonlinear dispersion relations are obtained and analyzed for both upstream and
downstream traveling waves.
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Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, Vol. 47, No. 3, pp. 43–48, May–June, 2006. 相似文献
17.
V. V. Ostapenko A. A. Malysheva 《Journal of Applied Mechanics and Technical Physics》2006,47(2):157-168
The solvability of the problem of the flows resulting from the incidence of a discontinuous wave on a bottom step is studied
using a single-layer shallow water model. Solutions in which the total energy of the flow is conserved at the step and those
in which it is lost at the step are considered. Regions of double and triple hystereses in the obtained self-similar solutions
are found. An analogy is drawn with the problem of single-layer flow over a bottom obstacle.
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Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, Vol. 47, No. 2, pp. 8–22, March–April, 2006. 相似文献
18.
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
19.
I. V. Sturova 《Journal of Applied Mechanics and Technical Physics》1999,40(4):604-610
Oblique incidence of small-amplitude waves on an elastic plate floating on a free liquid surface is studied. The reflection
and transmission factors of the waves and the vertical displacements and strains of the plate are determined. It is shown
that all these characteristics depend greatly on the incidence angle and frequency of the wave and the width of the plate.
Approximate solutions for the reflection and transmission factors are obtained.
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. 62–68, July–August, 1999. 相似文献
20.
The three-dimensional problem of finite-depth stratified flow over a small bottom irregularity is considered in mixed Euler-Lagrange variables. The Brunt-Väisälä frequency is assumed to be constant and small, and the free surface condition is replaced by the rigid roof condition. Investigation of the far field showed that the principal wave perturbations lie within an angle which for large values of the internal Froude number is much less than theKelvin angle, while the wave amplitude at infinity is of the order of l/r, where r is the polar radius. The ring perturbations are exponentially damped. As distinct from point source models, the model in question does not lead to divergence of the integrals on the flow axis [1-3]. Appproximate expressions for the radial and ring waves in terms of certain universai functions were obtained for investigating the near and far fields when the bottom irregularity is hemispherical. For the radial waves a law of similarity was obtained for which the characteristic dimension in the direction of the flow axis is the ratio of the flow velocity to the Brunt-Väisälä frequency, and the characteristic dimension in a direction perpendicular to the flow axis the depth of the fluid. In the first approximation the ring perturbations do not depend on the Brunt-Väisälä frequency. It is shown that in the near field the zone of intense wave perturbations is of the order of the fluid depth and not of the dimensions of the obstacle as for Kelvin ship waves on the surface of a homogeneous fluid.Translated from Izvestiya Akademii Nauk SSSR, Mekhanika Zhidkosti i Gaza, No. 5, pp. 86–94, September–October, 1987. 相似文献