Heat exchange between a selectively emitting liquid and a laminar gas flow in the presence of an external source of radiation

An investigation is conducted in the solution of a number of practical problems of the radiative and combined heat exchange in nonuniform systems having widely different physical properties. The processes of thermal interaction between the ocean and the atmosphere have been treated in the paper [1], the effect of thermal radiation on the melting and solidification of semitransparent crystals has been investigated in [2], the flow of a selectively emitting gas around the lateral surface of an object evaporating under the action of radiative heating has been discussed in [3], and heat transfer from a jet to the molten mass of glass in a glassmaking furnace tank has been investigated in [4]. The radiative and combined heat exchange between a selectively emitting liquid and a transparent heat-conducting laminar gas flow in the case of a specified external thermal radiation field is discussed in this paper. The energy conservation equations are set up taking into account the heat transfer by radiation, convection, and molecular thermal conduction. A differential approximation is used in calculating the values of the radiation fluxes. A system of fundamental computational equations is solved by the method of finite differences and iterations and by the Runge-Kutta method. The results of the calculations are presented in the form of graphs.Translated from Zhurnal Prikladnoi Mekhaniki i Tekhnicheskoi Fiziki, No. 3, pp. 116–122, May–June, 1976.     

Sound generation by a laser beam in a liquid with absorbing particles

Sound generation by a laser beam within a liquid, related to liquid boiling at absorption centers, has been studied relatively little. Acoustic effects upon liquid boiling in a laser beam were first reported in [1]. A change in the index of refraction of a liquid has been observed under the action of acoustical radiation of microbubbles formed on absorbing particles in the zone irradiated by a laser beam [2–4]. However direct measurements of acoustical radiation from a set of microbubbles uniformly distributed over the volume of laser beam-liquid interaction has yet to be performed, to the authors' knowledge. The present study is a preliminary report of results of an experimental study of this class of opticoacoustical phenomena.Translated from Zhurnal Prikladnoi Mekhaniki i Tekhnicheskoi Fiziki, No. 1, pp. 9–12, January–February, 1984.In conclusion, the authors consider it their pleasant duty to thank G. A. Askar'yan for evaluating the study and S. V. Luk'yanov for assistance in measuring the particle size distribution.     

Kinematics of a turbulent boundary layer

In the article an attempt is made, within the framework of the Navier-Stokes equations, to describe the field of the instantaneous velocities of a liquid in the region of a turbulent flow near the wall. It is assumed that the velocities of the liquid are determined by the field of the eddies arising in regions of ejections under the action of pressure pulses in the region near the wall.Translated from Izvestiya Akademii Nauk SSSR, Mekhanika Zhidkosti i Gaza, No. 5, pp. 34–40, September–October, 1973.     

Stability of a radiation-absorbing ionizing shock wave in an electromagnetic field

The linear stability of a radiation-absorbing ionizing shock wave (light detonation waves) in the presence of a uniform electromagnetic field is investigated. The applied electric field is considered to be normal to the wave front and the magnetic field to be parallel to the front and perpendicular to the plane in which perturbations propagate. The medium satisfies a two-parameter equation of state. Analytic stability criteria are obtained. For a perfect gas the effect of the electromagnetic field and radiation on shock wave stability is determined.Moscow. Translated from Izvestiya Rossiiskoi Akademii Nauk, Mekhanika Zhidkosti i Gaza, No. 1, pp. 23–30, January–February, 1996.     

The flow of a gas consisting of asymmetric dipole molecules in a field of resonance radiation

The special properties of the flow of a molecular gas in a field of continuous radiation the frequency of which is resonant to the frequency of the intermodal vibrational-rotational transition has been considered previously in [1]. However, this did not take account of a possibility of an energy flux arising from translational degrees of freedom of the gas molecules into vibrational degrees of freedom as a result of the rotational-translational (R-T) transfer. This effect was discussed in [2] for the absorption by a gas consisting of diatomic molecules of radiation momentum in the P-branch of a vibrational-rotational transition. As will be shown below, for asymmetric dipole molecules of the type similar to a symmetric and an asymmetric top, this mechanism of the resonance radiation effect may take place not only under absorption of the radiation in the P-branch, but also in the Q-, and even in the R-branch. The investigation of these effects in the flow of a gas consisting of asymmetric dipole molecules in a resonance radiation field forms the subject of the present study.Translated from Izvestiya Akademii Nauk SSSR, Mekhanika Zhidkosti i Gaza, No. 1, pp. 123–137, January–February, 1985.In conclusion we may note that the effects considered can have an important effect on the propagation both of continuous, and of intermittent electromagnetic radiation.     

Propagation of an electromagnetic wave in a coaxial cable. The case of a narrow gap

A study is made of the propagation of a discontinuity of the electromagnetic field in a magnet in a coaxial cable. The shape of a discontinuity of the electromagnetic field propagating along a magnet from a voltage source is found. Under the assumption of a small gap between coaxial, infinitely conducting cylinders, the field parameters behind the discontinuity are determined.Translated from Izvestiya Akademii Nauk SSSR, Mekhanika Zhidkosti i Gaza, No. 2, pp. 193–197, March–April, 1981.I thank A. G. Kulikovskii and V. V. Gogosov for a detailed discussion of the work.     

Sound waves in a magnetizable medium

This article considers the propagation of small perturbations in a medium which can be inhomogeneously and isotropically magnetized under the action of an electromagnetic field. It is shown that in such a medium there is the possibility of sound waves of the same kind as in a medium with a constant magnetic susceptibility. However, the phase velocities of fast and slow magnetosonic waves can take on imaginary values so that, in strong magnetic fields, there may arise the phenomenon of instability. Investigations were made of the diagrams of the phase velocities for para- and diamagnetic substances for a medium with magnetic saturation; the case of an incompressible medium is discussed.Translated from Zhurnal Prikladnoi Mekhaniki i Tekhnicheskoi Fiziki, No. 1, pp. 15–22, January–February, 1973.     

Asymptotic of the electromagnetic field above a layerlike anisotropic medium of high conductivity

The model of an anisotropic, layerlike medium is often employed in problems of electromagnetic probing, and many papers have been written on the propagation of an electromagnetic field in such media. A systematic exposition of such problems was set out by Tikhonov, Sku-garevskaya, and Dmitriev [1–6]. In this paper we shall construct an asymptotic for the electromagnetic field of a point source lying above a layerlike medium of finite anisotropy having a fairly high longitudinal and transverse conductivity, or in which the source lies at a considerable height above the medium. The principles here laid down for the construction of the asymptotic indicate quite clearly under what circumstances the asymptotic is feasible, and if necessary allow the next approximations to be taken into account.Translated from Zhurnal Prikladnoi Mekhaniki i Tekhnicheskoi Fiziki, No. 2, pp. 175–188, March–April, 1966.     

Effect of sound on a supersonic jet

It is known that under the influence of sound from an external source or the sound emitted by the supersonic jet itself at discrete frequencies in nonoptimal flow regimes the supersonic jet expands more rapidly and its range is reduced [1, 2], However, the mechanism of action of the sound on the supersonic jet has not been adequately investigated and, in particular, no one has determined the intensity of the external source capable of producing a marked change in the gas dynamic parameters of the jet, its characteristics or how the interaction process develops. These questions are examined below. By means of shadow photography with a pulsed light source it is shown that a significant change in the gas dynamic characteristics of the supersonic jet can be achieved by directing at its base along the normal to the jet boundary sound with an intensity corresponding to 0.1–0.2% of the total pressure in the jet. The appearance of large-scale disturbances on the irradiated side of jet and the directional emission of sound by the jet at the frequency of the external source are noted.Translated from Izvestiya Akademii Nauk SSSR, Mekhanika Zhidkosti i Gaza, No. 6, pp. 170–174, November–December, 1989.The author is grateful to A. A. Kochetkov for assisting with the work.     

Propagation of electromagnetic disturbances above a plane surface

Under certain assumptions, it is shown that the propagation problem for an electromagnetic disturbance becomes self-similar, and the self-similarity parameters are determined. A basis is given for the absence of reflection, and it is shown that it is equivalent to the boundary conditions of M. A. Leontovich. Solutions of the propagation problem are obtained for the various components of a pulsed signal field from a dipole of arbitrary orientation, and their properties studied.Translated from Zhurnal Prikladnoi Mekhaniki i Tekhnicheskoi Fiziki, No. 5, pp. 22–30, September–October, 1970.     

超高速碰撞产生的电磁辐射

超高速碰撞产生的电磁辐射是固体物质在强冲击作用下的重要物理响应,在深空探测、航天器对空间碎片的防护设计、武器毁伤评估应用广泛。本文中概述了超高速碰撞产生的电磁辐射现象,总结了不同碰撞条件下,超高速碰撞产生微波和闪光的时频特性;从超高速碰撞产生材料破碎和产生等离子体两个方面,分析了超高速碰撞产生微波的辐射模型;归纳了超高速碰撞下的发光机理,并阐述了超高速碰撞产生连续光谱和线谱的辐射模型,指出了超高速碰撞产生电磁辐射研究存在的不足与发展趋势。     

Effect of Joule dissipation on the convective instability of a conducting liquid with flow in a magnetic field

The results of [1] are extended to the case when the Joule dissipation leads to a nonlinear profile of the unperturbed temperature of the liquid. Convective instability of a conducting liquid, with flow in a magnetic field directed perpendicular to the flow, with a temperature-dependent distribution of the conductivity which is nonhomogeneous in the direction of action of the electromagnetic force, was discussed in [1], neglecting Joule dissipation. This type of approach permitted investigating an energy equation without electromagnetic terms, which to a certain degree facilitated the solution of the problem. In many cases, however, the Joule dissipation is considerable and may exert a considerable effect on the development of convective instability. Thus, without taking account of Joule evolution of heat, instability can arise only with positive values of the Rayleigh number, exceeding some critical value, while, at the same time, Joule dissipation may lead to a situation in which instability will develop also with negative values of the Rayleigh number, i.e., under conditions when the state without the evolution of Joule heat is absolutely stable.Moscow. Translated from Izvestiya Akademii Nauk SSSR, Mekhanika Zhidkosti i Gaza, No. 1, pp. 19–22, January–February, 1972.     

A Magnetoelastic Field in a Ferromagnetic Medium with a Spherical Cavity

The problem on the stress–strain state of an infinite isotropic body made of a magnetically soft material and containing a spherical cavity is considered. It is assumed that the body is under an external magnetic field. The basic characteristics of the stress–strain state and the magnetic field induced are determined and their singularities near the cavity are studied. Graphs are presented for the total magnitoelastic and Maxwell stresses as functions of the magnetic induction, the angle of dip, and the mechanical and magnetic properties of the material     

The Stress State of a Ferromagnetic with an Elliptic Crack in a Homogeneous Magnetic Field

The problem on the stress–strain state of an infinite isotropic body made of a magnetically soft material and containing an elliptic crack is considered. It is assumed that the body is under an external magnetic field perpendicular to the crack plane. The basic characteristics of the stress–strain state and the magnetic field induced are determined and their singularities near the elliptic crack are studied. Formulas are given for the stress intensity factors for the force and magnetic fields near the crack tip     

Thermo-mechanical response of tension panels under intense rapid heating

The temperature dependence of the fracture strength of 7075-T6 aluminum alloy was determined under rapid heating (0.02–.50 sec) conditions by exposing thin-section specimens to intense surface irradiation while under constant tensile load. When combined with a numerical thermal analysis and an appropriate limit analysis, these data enabled accurate prediction of the heating time required to produce ductile fracture in spot irradiated tension panels. The transient heat transfer model employed in the computations incorporated material removal due to melting, temperature-dependent material properties, and convection/radiation losses.     

Radiation and scattering of sound from a vortex ring

The mechanisms of generation and scattering of sound by a vortex ring are investigated on the basis of fluid dynamics. The vortex ring can serve as a simple dynamic model of the large-scale structures observed in shear flows. Moreover, it is probably the most easily studied vortex element that can be created experimentally. The sound scattering investigation also served to determine the extent to which the vortex is affected by sound, its selectivity with respect to such parameters as the acoustic frequency, the angle of incidence of the wave, etc. The perturbed motion is considered against the background of the steady-state motion of the ring. The perturbed motion in the vortex core is determined on the basis of linear incompressible fluid dynamics. Two terms of the expansion in the M number of the far acoustic field generated by the perturbations in the core are found in accordance with Lighthill's theory. The acoustic power and directivity of the radiation and the acoustic instability growth rate are calculated. It is shown that the scattering of sound by the vortex ring is a resonance effect, and the scattering amplitude near resonance is determined. The acoustic action on the hydrodynamic structure of the flow in the core of the ring is especially intense near the resonances and extends over a period short as compared with the characteristic time of the acoustic instability.Translated from Izvestiya Akademii Nauk SSSR, Mekhanika Zhidkosti i Gaza, No. 3, pp. 83–95, May–June, 1987.     

Optimization of electrodynamic acceleration regimes for cylindrical conductors

At the present time electromagnetic accelerators which use the action of an impulsive electromagnetic field on a current-carrying conductor appear to be promising devices for the study of high-speed collisions. In the regime using separate sources for the accelerating magnetic field and the current in the conductor being accelerated it is possible to bring cylindrical conductors up to velocities exceeding 12 km/sec [1]. Acceleration regimes have been calculated previously [2] assuming independence of the current density in the conductor from the accelerating magnetic field. However, as analysis of transient electromagnetic processes occurring in the interaction of an impulsive electromagnetic field with a cylindrical conductor shows [3], the maximum current density, limited by heating conditions, depends significantly on the induction of the accelerating magnetic field. In the present study we will analyze regimes for electrodynamic acceleration of cylindrical conductors with consideration of diffusion of both the intrinsic and the external impulsive magnetic field within the conductor.Translated from Zhurnal Prikladnoi Mekhaniki i Tekhnicheskoi Fiziki, No. 6, pp. 24–28, November–December, 1985.In conclusion, the author considers it his pleasant duty to express his gratitude to V. N. Bondaletov for his valuable device.     

Gasdynamic structure of the heliosphere: Theory and experiment

Gasdynamic models of the solar wind interaction with the ambient interstellar medium are reviewed. The model associated with supersonic flow around the solar wind by the interstellar gas stream is analyzed in more detail. This model is based on the fact that the supersonic motion of the interstellar hydrogen and argon relative to the sun has been established by spacecraft experiments to investigate the scattered solar radiation at wavelengths 1216 A and 584 A. The creation of an adequate gasdynamic model of the flow is especially topical in connection with the missions of the Voyager 1 and 2, Pioneer 10 and 11, Ulysses, and international probe spacecraft. New unsolved theoretical problems relating to the correct interpretation of the experimental data are formulated.Translated from Izvestiya Rossiiskoi Akademii Nauk, Mekhanika Zhidkosti i Gaza, No. 3, pp. 3–24, May–June, 1993.     

Elasticity-theoretic plane problem for an anisotropic body subject to an electrical effect

The elastic properties of the body are assumed inseparable from its electrical properties (piezoelectric effect). The static problem is considered for an infinitely long homogeneous rod under the action of a plane system of forces or a lengthwise uniform distribution of electric field potential. The general equations of theory of elasticity and of electrical field theory, together with the piezoelectric relationships, are used. Conditions on the material parameters are obtained, under which a plane electric field and a plane deformation state appear in the body.Translated from Zhurnal Prikladnoi Mekhaniki i Tekhnicheskoi Fiziki, Vol. 11, No. 2, pp. 96–103. March–April, 1970.     

Simulation and experimental studies of a vibro-impact capsule system driven by an external magnetic field

This paper studies the electromagnetic field used for driving a vibro-impact capsule prototype for small bowel endoscopy. Mathematical models of the electromagnetic field and the capsule system are introduced, and analytical solution of the magnetic force applied on the capsule is derived and verified by experiment. The impact force between the inner mass of the capsule and the capsule body is also compared via numerical simulation and experimental testing. By comparing the capsule’s progressions under different control parameters (e.g. the excitation frequency and duty cycle), the merits of using the vibro-impact propulsion are revealed. Based on the experimental results, the optimised speed of the prototype can achieve up to 3.85 mm/s. It is therefore that the potential feasibility of using the external electromagnetic field for propelling the vibro-impact capsule system is validated.