共查询到20条相似文献,搜索用时 46 毫秒
1.
A. E. Bukatov 《Fluid Dynamics》1994,29(4):549-555
The nonlinear interaction of periodic traveling waves of the first and second harmonics in a constant-depth uniform fluid
covered with broken ice is considered. Uniform asymptotic expansions up to third-order values for the velocity potential of
the fluid and the elevation of the basin surface are found by means of the multivariable expansion procedure. The dependence
of the wave perturbations on the thickness of the ice and the interacting-harmonic characteristics is analyzed.
Sevastopol. Translated from Izvestiya Rossiiskoi Akademii Nauk, Mekhanika Zhidkosti i Gaza, No. 4, pp. 136–143, July–August,
1994. 相似文献
2.
The self-consistent motion of a fluid and elastically oscillating plates partially covering the fluid is simulated numerically
in the linear approximation. The problem is reduced to the simultaneous solution of the Laplace equation for the fluid and
the equation of elastic plate oscillations for the ice. The numerical and analytical solutions, the latter obtained from an
integral equation containing the Green’s function, are compared. To solve the problem numerically, the boundary element method
for the Laplace equation and the finite element method for the equation describing the elastic plate are proposed. The coefficients
of transmission and reflection of surface gravity waves from the floating plates are calculated. It is shown that the solution
may be quasi-periodic with characteristics determined by the initial values of the wave and ice-floe parameters. The ice floes
may exert a filtering effect on the surface wave spectrum, essentially reducing its most reflectable components.
Sankt-Peterburg. Translated from Izvestiya Rossiiskoi Akademii Nauk, Mekhanika Zhidkosti i Gaza, No. 3, pp. 123–131, May–June,
2000. 相似文献
3.
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
4.
Yu. E. Ivanova V. E. Ragozina 《Journal of Applied Mechanics and Technical Physics》2006,47(6):892-898
The method of matched asymptotic expansions was employed to obtain approximate solutions to the one-dimensional boundary-value
problems of nonlinear dynamic elasticity theory of impact loading on the surface of a cylindrical cavity of an incompressible
medium that causes antiplane motion or torsion of the medium. The expansion of the solution in the near-front region is based
on solutions of evolution equations different from the equations for quasi-simple waves.
__________
Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, Vol. 47, No. 6, pp. 144–151, November–December, 2006. 相似文献
5.
A. Mahalov M. Moustaoui B. Nicolaenko K. L. Tse 《Theoretical and Computational Fluid Dynamics》2007,21(6):399-422
The generation and physical characteristics of inertia-gravity waves radiated from an unstable forced jet at the tropopause
are investigated through high-resolution numerical simulations of the three-dimensional Navier–Stokes anelastic equations.
Such waves are induced by Kelvin–Helmholtz instabilities on the flanks of the inhomogeneously stratified jet. From the evolution
of the averaged momentum flux above the jet, it is found that gravity waves are continuously radiated after the shear-stratified
flow reaches a quasi-equilibrium state. The time–vertical coordinate cross-sections of potential temperature show phase patterns
indicating upward energy propagation. The sign of the momentum flux above and below the jet further confirms this, indicating
that the group velocity of the generated waves is pointing away from the jet core region. Space–time spectral analysis at
the upper flank level of the jet shows a broad spectral band, with different phase speeds. The spectra obtained in the stratosphere
above the jet show a shift toward lower frequencies and larger spatial scales compared to the spectra found in the jet region.
The three-dimensional character of the generated waves is confirmed by analysis of the co-spectra of the spanwise and vertical
velocities. Imposing the background rotation modifies the polarization relation between the horizontal wind components. This
out-of-phase relation is evidenced by the hodograph of the horizontal wind vector, further confirming the upward energy propagation.
The background rotation also causes the co-spectra of the waves high above the jet core to be asymmetric in the spanwise modes,
with contributions from modes with negative wavenumbers dominating the co-spectra.
Dedicated to the memory of our colleague Dr. Binson Joseph 相似文献
6.
Yu. V. Sanochkin 《Fluid Dynamics》2000,35(4):599-604
The frequencies and damping coefficients of gravitational-capillary waves are found for a wide range of controlling dimensionless
parameters. The transition to the limiting cases of deep water and an ideal fluid is analyzed. In the parameter plane, the
boundary between the regions of oscillatory and aperiodic perturbations is determined and the region of weak damping is indicated.
The equilibrium state of thin liquid films with account for the Van der Waals forces is considered and the dispersion equation
for the capillary-Van der Waals surface waves is obtained. For a suitably chosen frequency scale, this equation is the same
as that for gravitational-capillary waves. The physical conditions making it possible to observe capillary and Van der Waals
waves in thin fluid layers are estimated.
Moscow. Translated from Izvestiya Rossiiskoi Akademii Nauk, Mekhanika Zhidkosti i Gaza, No. 4, pp. 156–164, July–August, 2000. 相似文献
7.
O. V. Voinov 《Journal of Applied Mechanics and Technical Physics》2007,48(3):385-392
The motion of thin films of a viscous incompressible liquid in a gas under the action of capillary forces is studied. The
surface tension depends on the surfactant concentration, and the liquid is nonvolatile. The motion is described by the well-known
model of quasi-steady-state viscous film flow. The linear-wave solutions are compared with the solution using the Navier-Stokes
equations. Situations are studied where a solution close to the inviscid two-dimensional solutions exists and in the case
of long wavelength, the occurrence of sound waves in the film due to the Gibbs surface elasticity is possible. The behavior
of the exact solutions near the region of applicability of asymptotic equations is studied, and nonmonotonic dependences of
the wave characteristics on wavenumber are obtained.
__________
Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, Vol. 48, No. 3, pp. 103–111, May–June, 2007. 相似文献
8.
S. F. Dotsenko 《Fluid Dynamics》1978,13(5):658-663
The development of three-dimensional waves generated by a region of pressures moving uniformly and rectilinearly over the surface of a thin elastic isotropic plate covering an ideal fluid layer of finite depth is investigated. The pressures act starting at a certain instant. A qualitative similarity between the waves occurring and gravity-capillary waves is noted. The calculations are made for an ice cover. This model problem permits examining a number of properties of the oscillations of the ice cover occurring when hauling freight over ice roads, landing and takeoff of aircraft from ice fields, etc. [1]. The development of ship waves in a fluid of finite depth in the absence of a floating plate was investigated in [2, 3] and gravity-capillary waves were studied in [4–6]. Certain properties of steady three-dimensional waves occurring during movement of a load over the surface of a floating elastic plate were established in [1].Translated from Izvestiya Akademii Nauk SSSR, Mekhanika Zhidkosti i Gaza, No. 5, pp. 26–32, September–October, 1978. 相似文献
9.
A three-dimensional nonstationary problem of vibrations of a flexible shell moving on the surface of an ideal heavy fluid.
The forces due to surface tension are ignored. The problem is formulated in the space of the acceleration potential. The potential
of the pulsating source is found by solving the Euler equation and the continuity equation taking into account the free-surface
conditions (linear theory of small waves) and the conditions at infinity. The density distribution function of the dipole
layer is determined from the boundary conditions on the surface of the shell. Formulas for determining the shape of gravity
waves on the fluid surface and the natural frequencies of vibrations of the shell are obtained.
__________
Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, Vol. 50, No. 4, pp. 66–75, July–August, 2009. 相似文献
10.
V. M. Fomin V. F. Chirkashenko V. F. Volkov A. M. Kharitonov 《Journal of Applied Mechanics and Technical Physics》2008,49(6):962-970
The possibility of controlling the sonic boom level by means of cooling the surface of a flying vehicle is discussed. The
effect of surface cooling on the formation of the perturbed flow structure at large distances from the vehicle is demonstrated
by an example of a modified power-law body of revolution. The intensity of the intermediate shock wave and the perturbed pressure
pulse near the body are seen to decrease, which expands the altitude range of the region where the sonic boom is reduced (down
to 50%). At larger distances from the body, cryogenic forcing ensures a 12% decrease in the bow shock wave intensity. The possibility of controlling the process of formation of wave structures near
the surface, such as barrel shock waves, is demonstrated. An explanation of the cryogenic forcing mechanism is offered.
__________
Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, Vol. 49, No. 6, pp. 88–98, November–December, 2008. 相似文献
11.
V. M. Kozin A. V. Pogorelova 《Journal of Applied Mechanics and Technical Physics》1999,40(6):1036-1041
The uniformly accelerated motion of an amphibian air-cushion vehicle on the surface of a basin covered by finely small ice
floes is considered.
Institute of Machine Science and Metallurgy, Far-Eastern Division, Russian Academy of Sciences, Komsomol'sk-on-Amur 681005.
Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, Vol. 40, No. 6, pp. 48–53, November–December, 1999. 相似文献
12.
The far field asymptotics of internal waves is constructed for the case when a point source of mass moves in a layer of arbitrarily
stratified fluid with slowly varying bottom. The solutions obtained describe the far field both near the wave fronts of each
individual mode and away from the wave fronts and are expansions in Airy or Fresnel waves with the argument determined from
the solution of the corresponding eikonal equation. The amplitude of the wave field is determined from the energy conservation
law along the ray tube. For model distributions of the bottom shape and the stratification describing the typical pattern
of the ocean shelf eract analytic expressions are obtained for the rays, and the properties of the phase structure of the
wave field are analyzed.
Moscow. Translated from Izvestiya Rossiiskoi Akademii Nauk, Mekhanika Zhidkosti i Gaza, No. 3, pp. 111–120, May–June, 1998.
This work was financially supported by the Russian Foundation for Basic Research (project No. 96-01-01120). 相似文献
13.
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.
__________
Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, Vol. 47, No. 4, pp. 115–123, July–August, 2006. 相似文献
14.
N. D. Dikovskaya B. Yu. Zanin 《Journal of Applied Mechanics and Technical Physics》1999,40(1):108-113
The problem of the origin and evolution of two-dimensional waves of unstable disturbances in the boundary layer on an airfoil
in the region of adverse pressure gradient in the preseparation flow region is solved numerically. The stability of the experimental
velocity profiles, including the inflected profiles, is studied. As a result of the calculations, the boundaries of the instability
region and the parameters of the maximally unstable disturbances (frequency, growth rate, wavelength, and propagation velocity)
are determined for each velocity profile. The characteristics obtained in the present work are in good agreement with the
real experimental parameters of instability waves.
Institute of Theoretical and Applied Mechanics, Siberian Division, Russian Academy of Sciences, Novosibirsk 630090. Translated
from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, Vol. 40, No. 1, pp. 126–132, January–February, 1999. 相似文献
15.
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
16.
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.
__________
Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, Vol. 47, No. 3, pp. 3–11, May–June, 2006. 相似文献
17.
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.
__________
Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, Vol. 47, No. 3, pp. 43–48, May–June, 2006. 相似文献
18.
Steady-state rectilinear motion of a load on an ice sheet modeled by a viscoelastic plate is considered. The viscoelastic
properties of ice are described using the linear Maxwell and Kelvin-Voigt models and a generalized Maxwell-Kelvin model. Calculated
vertical displacements and strains of the ice plate are compared with available experimental data.
__________
Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, Vol. 50, No. 3, pp. 147–157, May–June, 2009. 相似文献
19.
V. D. Zhestkaya 《Journal of Applied Mechanics and Technical Physics》1999,40(4):770-775
A method for analyzing the bending of an ice sheet subjected to a moving load is proposed. The problem is solved in a dynamic
formulation. The algorithm of solution is based on the finiteelement method and the finite-difference method. The method proposed
allows one to determine the stress-strain state of an ice sheet for any law of motion of a load over ice. Two versions of
initial conditions are considered. Examples of calculations are given.
Komsomol’sk-on-Amur State Technical University, Komsomol’sk-on-Amur 681013. Translated from Prikladnaya Mekhanika i Tekhnicheskaya
Fizika, Vol. 40, No. 4, pp. 243–248, July–August, 1999. 相似文献
20.
Vera Mikyoung Hur 《Archive for Rational Mechanics and Analysis》2008,188(2):213-244
The solitary water wave problem is to find steady free surface waves which approach a constant level of depth in the far field.
The main result is the existence of a family of exact solitary waves of small amplitude for an arbitrary vorticity. Each solution
has a supercritical parameter value and decays exponentially at infinity. The proof is based on a generalized implicit function
theorem of the Nash–Moser type. The first approximation to the surface profile is given by the “KdV” equation. With a supercritical
value of the surface tension coefficient, a family of small amplitude solitary waves of depression with subcritical parameter
values is constructed for an arbitrary vorticity. 相似文献