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1.
A new type of flow in a magnetic fluid has been experimentally detected and investigated. The interaction between an alternating
nonuniform magnetic field and a magnetic fluid leads to the parametric excitation of traveling capillary-gravitational waves
which are the direct cause of the average flow. A necessary condition of formation of hydrodynamic flows in an alternating
field is also the presence of time-dependent harmonics with multiple frequencies synchronized with the first harmonic, so
that the time dependence of the ponderomotive force is generally pulsed. It is shown that for plane vibrational flows the
classical theory cannot explain the high intensity of the average flows observed. It is suggested that the high intensity
of magnetovibrational flows is related to the violation of the cylindrical symmetry of the traveling capillary-gravitational
waves and the transition to a three-dimensional motion.
Perm’. Translated from Izvestiya Rossiiskoi Akademii Nauk, Mekhanika Zhidkosti i Gaza, No. 1, pp. 124–133, January–February,
1998. 相似文献
2.
It is shown that the critical Rayleigh number which characterizes the stability of a thin charged viscous fluid film on the
surface of a rigid spherical core develops rapidly with decrease in the film thickness to 100 nm when the effect of the disjoining
pressure becomes significant. The dependence of the instability growth rate on the thickness of the fluid layer is obtained
by analyzing the dispersion relation numerically.
Yaroslavl’. Translated from Izvestiya Rossiiskoi Akademii Nauk, Mekhanika Zhidkosti i Gaza, No. 1, pp. 102–106, January–February,
1999. 相似文献
3.
The problem of the magnetic field-driven rotation of a magnetic fluid droplet in a viscous nonmagnetic fluid is solved analytically
and experimentally. The shape of the droplet and the magnetic fields and velocities of both fluids are calculated in the weak-field
approximation. The droplet is flattened for any relations between the parameters of the system. The instability of the axisymmetric
shape of the droplet is established experimentally. A result of the instability is a sudden change in the droplet shape from
a flattened ellipsoid of revolution to a triaxial ellipsoid elongated in the equatorial plane. The critical magnetic Bond
number is determined.
Perm’. Translated from Izvestiya Rossiiskoi Akademii Nauk, Mekhanika Zhidkosti i Gaza, No. 1, pp. 22–30, January–February,
2000.
The work was carried out with the support of the Russian Foundation for Basic Research (project No. 98-01-00182). 相似文献
4.
V. A. Chugunov L. D. Eskin S. L. Tonkonog 《Journal of Applied Mechanics and Technical Physics》2000,41(2):267-272
The problem of exhaustion of a thin film of a non-Newtonian fluid with a power rheological law from a slotted orifice is solved
with account of film slipping relative to the underlying surface. By the method of group analysis with transformation of the
parameters entering the problem, an asymptotic formula for the film profile is obtained and a law of motion of the film edge
with small slipping is derived.
Kazan' State University, 420008 Kazan'. Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, Vol. 41, No. 2, pp.
71–76, March–April, 2000. 相似文献
5.
The processes of interaction between concentrated energy fluxes and solid targets have been investigated in a number of studies.
The generation of magnetic fields in erosional plasma formations has been experimentally observed [1–4]. However, the evolution
of magnetic fields in plasma jets has not yet been studied in sufficient detail. This paper is devoted to a numerical investigation
of unsteady three-dimensional erosion plasma flows and the generation in those flows of magnetic fields resulting from the
action of laser radiation on solid targets.
Translated from Izvestiya Akademii Nauk SSSR, Mekhanika Zhidkosti i Gaza, No. 6, pp. 135–140, November–December, 1986.
The authors are grateful to I. V. Nemchinov and B. T. Fedyushin for useful discussion of their results. 相似文献
6.
S. N. Samatov O. Yu. Tsvelodub 《Journal of Applied Mechanics and Technical Physics》1999,40(4):630-637
A thin film of a viscous fluid flowing down a vertical plane in a gravitational field is considered. The plane executes harmonic
oscillations in the direction normal to itself. An equation that describes the evolution of surface disturbances at small
fluid flow rates is obtained. Some solutions of this equation are found.
Kutateladze Institute of Thermal Physics, Siberian Division, Russian Academy of Sciences, Novosibirsk 630090. Translated from
Prikladnaya Mekhanika i Tekhnicheskaya Fizika, Vol. 40, No. 4, pp. 90–98, July–August, 1999. 相似文献
7.
O. V. Voinov 《Journal of Applied Mechanics and Technical Physics》2000,41(4):666-669
We consider the creeping motion of a thin layer of a nonvolatile viscous fluid spreading due to capillary forces over a rigid
surface covered by a thin homogeneous film (microfilm). The influence of van der Waals forces on the asymptotic slope of the
free boundary of the layer is studied in the region of large thickness, where capillary forces dominate. A solution of the
problem of the slope angle is obtained for the entire possible range of the microfilm thickness. In the limit of small thickness
of the microfilm, this solution is in agreement with the well-known solution of the problem of the dynamics of wetting of
a dry surface in the presence of a precursory film and van der Waals forces. The role of the condition at the end of the precursory
film is studied.
Institute of Mechanics of Multiphase Systems, Siberian Division, Russian Academy of Sciences. Tyumen' 625000. Translated from
Prikladnaya Mekhanika i Tekhnicheskaya Fizika. Vol. 41, No. 4, pp. 101–105, July–August. 2000. 相似文献
8.
A. V. Proskurin A. M. Sagalakov 《Journal of Applied Mechanics and Technical Physics》2008,49(3):383-390
The stability of the plane flow of an electrically conducting fluid with respect to small perturbations was studied at large
Reynolds numbers in the presence of a longitudinal magnetic field. The dependence of the critical Reynolds number on the electrical
conductivity is investigated. At large Reynolds numbers, a new branch of instability and a sudden change in the critical Reynolds
numbers is found.
__________
Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, Vol. 49, No. 3, pp. 45–53, May–June, 2008. 相似文献
9.
Bernd Schmidt 《Archive for Rational Mechanics and Analysis》2008,190(1):1-55
We give a rigorous derivation of a continuum theory from atomic models for thin films. This scheme has been proposed by Friesecke and James in [J. Mech. Phys. Solids
48, 1519–1540 (2000)]. The resulting continuum energy expression is obtained by integrating a stored energy density which not
only depends on the deformation gradient, but also on ν-1 director fields when ν is the (fixed) number of atomic film layers. 相似文献
10.
We explore the effects of fluid films of variable depths on droplets impacting into them. Corresponding to a range of fluid
“film” depths, a non-dimensional parameter—H*, defined as the ratio of the film thickness to the droplet diameter—is varied in the range 0.1≤H*≤10. In general, the effect of the fluid film imposes a dramatic difference on the dynamics of the droplet–surface interaction
when compared to a similar impact on a dry surface. This is illustrated by the size distribution and number of the splash
products. While thin fluid films (H*≈0.1) promote splashing, thicker films (1≤H*≤10) act to inhibit it. The relative roles of surface tension and viscosity are investigated by comparison of a matrix of
fluids with low and high values of these properties. Impingement conditions, as characterized by Reynolds and Weber numbers,
are varied by velocity over a range from 1.34 to 4.22 m/s, maintaining a constant droplet diameter of 2.0 mm. The dependence
of splashing dynamics, characterized by splash product size and number, on the fluid surface tension and viscosity and film
thickness are discussed. 相似文献
11.
Sloshing behavior of a magnetic fluid in a cylindrical container 总被引:1,自引:0,他引:1
Sloshing of a magnetic fluid in a laterally vibrated cylindrical container subject to a non-uniform vertical magnetic field
was examined. Internal velocity profiles were measured using ultrasound Doppler velocimetry. The effect of the magnetic field
on the resonant frequency of the fluid–container system was examined and the results were compared with theoretical results.
The second and third peaks of the power spectra of velocity shifted to lower frequencies as the magnetic field was increased.
It was observed that these derived frequency peaks were connected with swirling in the cylindrical container.
Received: 9 May 2000 / Accepted: 29 May 2001 Published online: 29 November 2001 相似文献
12.
Yongbin Zhang 《Theoretical and Computational Fluid Dynamics》2009,23(4):239-254
Boundary film shear elastic modulus effect is analyzed in a hydrodynamic contact. The contact is one-dimensional composed
of two parallel plane surfaces, which are, respectively, rough rigid with rectangular micro projections in profile periodically
distributed on the surface and ideally smooth rigid. The whole contact is consisted of cavitated area and hydrodynamic area.
The hydrodynamic area consists of many micro Raleigh bearings which are discontinuously and periodically distributed in the
contact. Analysis is thus carried out for a micro Raleigh bearing in this contact. The hydrodynamic contact in this micro
Raleigh bearing consists of boundary film area and fluid film area which, respectively, occur in the outlet and inlet zones.
In boundary film area, the film slips at the upper contact surface due to the limited shear stress capacity of the film–contact
interface, while the film does not slip at the lower contact surface due to the shear stress capacity large enough at the
film–contact interface. In boundary film area, the viscosity, density and shear elastic modulus of the film are varied across
the film thickness due to the film–contact interactions, and their effective values are used in modeling, which depend on
the film thickness. The analytical approach proposed by Zhang (J Mol Liq 128:60–64, 2006) and Zhang et al. (Int J Fluid Mech
Res 30:542–557, 2003) is used for boundary film area. In fluid film area, the film does not slip at either of the contact
surfaces, and the shear elastic modulus of the film is neglected. Conventional hydrodynamic analysis is used for fluid film
area. The present paper presents the theoretical analysis and a typical solution. It is found that for the simulated case
the boundary film shear elastic modulus effects on the mass flow through the contact, the overall film thickness of the contact
and the carried load of the contact are negligible but the boundary film shear elastic modulus effect on the local film thickness
of the contact may be significant when the boundary film thickness is on the 1 nm scale and the contact surfaces are elastic.
In Part II will be presented detailed results showing boundary film shear elastic modulus effects in different operating conditions.
相似文献
相似文献
13.
The dynamic behavior of a magnetic fluid in a laterally vibrated rectangular container subject to a non-uniform vertical
magnetic field has been investigated. Flow behavior was observed using the ultrasound velocity profile measuring technique.
The effect of the magnetic field on the resonant frequency of the fluid-container system is discussed. Experimental results
are compared with the results obtained from nonlinear theory using the perturbation method.
Received: 27 May 1997/Accepted: 26 March 1998 相似文献
14.
O. M. Ostrikov 《Journal of Applied Mechanics and Technical Physics》2006,47(4):596-599
The effect of thin polyparaxylene films on the mechanical twinning of bismuth single crystals with the (111) surface subjected
to local deformation. It is found that the number of twins formed near the stress concentrator increases in the presence of
the film. Possible mechanisms are proposed to explain an increase in the mobility of twin dislocations in a deformable crystal
whose surface is coated with a polyparaxylene film. Spalling of bismuth is found in the regions deformed by the indenter.
__________
Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, Vol. 47, No. 4, pp. 162–166, July–August, 2006. 相似文献
15.
Germanium is an important element in semiconductor and microelectronics industries. Its thermal conductivity is an invariable
and isotropic parameter in germanium crystal in the same temperature and its thermal conductivity is difficult to be measured
in thin film. In the present paper, using the non-equilibrium molecular dynamics simulation method and Stillinger–Weber potential
model, the normal and tangential thermal conductivity of germanium thin film are studied. There are remarkable anisotropy
and size effect of thermal conductivity in normal and tangential direction of germanium thin film. In the theoretical analysis,
Boltzmann transport theory is used to analyze the phonon transport in germanium thin film. Theoretical results further demonstrate
the anisotropy and size effect of thermal conductivity in thin film, which indicate the significant decrease of phonon mean
free path and predominant boundary phonon scattering in germanium thin film. 相似文献
16.
The nonlinear convective instability of a plane horizontal conducting fluid layer placed in a uniform vertical magnetic field
is studied [1]. A similar problem was previously considered in [2] but with allowance only for so-called weakly nonlinear
third-order effects. In the present paper attention is concentrated on the study of the finite-amplitude instability mechanisms
associated with the "hard" excitation of vibrations.
Moscow. Translated from Izvestiya Rossiiskoi Akademii Nauk, Mekhanika Zhidkosti i Gaza, No. 1, pp. 23–28, January–February,
1998. 相似文献
17.
The process of quenching cylindrical steel specimens in a magnetic fluid in the presence of a magnetic field is investigated. It is shown that depending on the strength of the magnetic field and its orientation with respect to the surface of the cylinder, local vapor formations that result in nonuniform cooling may appear on the surface and that the boiling of the fluid on the surface may take place in different regimes. The processes of formation of local vapor films were experimentally modeled by observing the shape of the surface of the magnetic fluid surrounding a cylinder placed between the poles of an electromagnet. An equation describing the shape of the free surface of the magnetic fluid and the evolution of the air pockets with variation of the volume of magnetic fluid and the strength of the magnetic field is derived. The surface shape of the magnetic fluid calculated from the theory proposed is shown to be in good agreement with the experimental data.Translated from Izvestiya Akademii Nauk SSSR, Mekhanika Zhidkosti i Gaza, No. 2, pp. 3–11, March–April, 1989. 相似文献
18.
E. I. Bichenkov 《Journal of Applied Mechanics and Technical Physics》2000,41(5):792-805
This paper deals with phenomena leading to a considerable increase in magnetic field and energy density during compression
of a magnetic flux trapped by a conducting shell and joint deformation of a magnetic field and material. The main features
and merits of these two alternative schemes of magnetic cumulation are discussed. A comparison is made between the classical
and schock-wave schemes of magnetic compression in a material with a phase transition from a nonconducting to a conducting
state. The possibility of magnetic-energy cumulation during stretching of magnetic field line by a transverse flow of a conducting
material is considered.
Lavrent’ev Institute of Hydrodynamics, Russian Academy of Sciences, Novosibirsk 630090. Translated from Prikladnaya Mekhanika
i Tekhnicheskaya Fizika, Vol. 41, No. 5, pp. 32–47, September–October, 2000. 相似文献
19.
The laminar flow of a thin layer of heavy viscous magnetic liquid down an inclined wall is examined. The stability and control of the flow of an ordinary liquid are affected only by alteration of the angle of inclination of the solid wall and the velocity of the adjacent gas flow. When magnetic liquids are used [1, 2], an effective method of flow control may be control of the magnetic field. By using magnetic fields of various configurations it is possible to control the flow of a thin film of viscous liquid, modify the stability of laminar film flow, and change the shape of the free surface of the laminarly flowing thin film, a factor which plays a role in mass transfer, whose rate depends on the phase contact surface area. The magnetic field significantly affects the shape of the free surface of a magnetic liquid [3, 4]. In this paper the velocity profile of a layer of viscous magnetic liquid adjoining a gas flow and flowing down an inclined solid wall in a uniform magnetic field is found. It is shown that the flow can be controlled by the magnetic field. The problem of stability of the flow is solved in a linear formulation in which perturbations of the magnetic field are taken into account. The stability condition is found. The flow stability is affected by the nonuniform nature of the field and also by its direction.Translated from Izvestiya Akademii Nauk SSSR, Mekhanika Zhidkosti i Gaza, No. 5, pp. 59–65, September–October, 1977. 相似文献
20.
The effect of shear flow (flow in a circular tube) on the process of relaxation of the magnetization of a magnetic fluid is investigated theoretically and experimentally. The experiments reveal a jump in the high-frequency susceptibility when the flow stops. This jump depends on the measurement frequency on the interval from 2 to 40 kHz, on the flow rate and on the structure of the magnetic fluid. A theory describing the dependence of the jump in high-frequency susceptibility on the frequency and the structure and flow rate of the fluid is proposed. The theory is found to be consistent with the experimental data.Translated from Izvestiya Akademii Nauk SSSR, Mekhanika Zhidkosti i Gaza, No. 6, pp. 94–98, November–December, 1988. 相似文献