Showing papers in "Journal of Applied Mechanics and Technical Physics in 1972"
TL;DR: In this article, the stability of steady nonlinear waves on the surface of an infinitely deep fluid with a free surface was studied. And the authors considered the problem of stability of surface waves as part of the more general problem of nonlinear wave in media with dispersion.
Abstract: We study the stability of steady nonlinear waves on the surface of an infinitely deep fluid [1, 2]. In section 1, the equations of hydrodynamics for an ideal fluid with a free surface are transformed to canonical variables: the shape of the surface η(r, t) and the hydrodynamic potential ψ(r, t) at the surface are expressed in terms of these variables. By introducing canonical variables, we can consider the problem of the stability of surface waves as part of the more general problem of nonlinear waves in media with dispersion [3,4]. The resuits of the rest of the paper are also easily applicable to the general case.
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TL;DR: In this article, the existence of invariant solutions of Navier-Stokes equations has been studied in the context of boundary value problems of S/H systems, and certain invariants of these problems have been proved.
Abstract: We examine certain invariant solutions of the Navier-Stokes equations. We prove theorems concerning the existence of solutions of boundary-value problems of the corresponding S/H systems.
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TL;DR: In this article, it was shown that in order to predict the shock Hugoniot of any substance up to a compression ratio equal to two, it is sufficient to know the initial density and the initial compressibility.
Abstract: It is shown that in order to predict the shock Hugoniot of any substance up to a compression ratio equal to two it is sufficient to know the initial density and the initial compressibility. The possibility of finding a priori the equations of state of nonporous mixtures of two substances, porous samples, and solutions is discussed.
TL;DR: In this paper, the relaxation of the vibrational energy in a mixture of polyatomic gases, which are ones with molecules simulated by harmonic oscillators, has been studied and the most general case is envisaged, where the energy relaxation occurs not only via vibrational-translational transitions but also via multiquantum vibrational exchange involving an arbitrary number of vibrational modes.
Abstract: Kinetic equations are derived for the relaxation of the vibrational energy in a mixture of polyatomic gases, which are ones with molecules simulated by harmonic oscillators. The most general case is envisaged, where the energy relaxation occurs not only via vibrational-translational transitions but also via multiquantum vibrational exchange involving an arbitrary number of vibrational modes. The analysis also incorporates the possible degeneracy of each mode when the molecules colliding are the same. An expression is derived that extends previous results [1–6] and that relates the vibrational temperatures in the case of quasiequilibrium. Equations are derived for the vibrational relaxation for the CO2-N2 case.
TL;DR: In this paper, an experimental investigation of the convective plume above a fine horizontal wire, heated by a constant current in air and in water, was performed using the IAB-451 shadow instrument in the diffraction interferometry method.
Abstract: Results are presented of an experimental investigation of the convective plume above a fine horizontal wire, heated by a constant current in air and in water. The temperature distribution in the plume was investigated using the IAB-451 shadow instrument in the diffraction interferometry method. The experimental results are in good agreement with laminar convection theories above a linear heat source. In the air, a comparison was made with the experimental results of other authors.
TL;DR: In this article, a generalization of the two-zone problem is presented, which makes it possible to go over to the analysis of a complex, multizone front and shows that, for a front with two reactions (in the condensed phase and in the gas) and with dispersion, there are in all three possible arrangements of the zones of heat evolution (two three-zone variants and one twozone variant) all possible types of dependence of the combustion rate on the depth of the dispersion are found.
Abstract: In the general case the combustion of condensed systems is of a stage-wise character and the combustion front is multizone [1, 2]. Following the investigation of two-zone models [3–5] it became clear that, during multizone combustion, one of the zones of heat evolution is the controlling zone. The velocity of the front is equal to the velocity of the controlling zone; however, with a change in the parameters of the system, there is the possibility of a transition of the controlling role from one zone to another, as well as of the coalescence and splitting of zones. This paper discusses a generalization of the two-zone problem which makes it possible to go over to the analysis of a complex, multizone front and shows that, for a front with two reactions (in the condensed phase and in the gas) and with dispersion, there are in all three possible arrangements of the zones of heat evolution (two three-zone variants and one two-zone variant). All possible types of dependence of the combustion rate on the depth of the dispersion are found.
TL;DR: In this paper, the authors investigated the trajectories of particles in a gently toroidal stellarator in the absence of collisions and determined the distribution function for the particles in the presence of collisions.
Abstract: Particle trajectories in a gently toroidal stellarator are investigated. The distribution function for the particles is determined in the absence of collisions.
TL;DR: In this article, the rotational temperature of nitrogen and its concentration in front of a spherically blunt cylinder situated on the axis of a supersonic rarefied jet was measured.
Abstract: This paper gives the results of electron-beam measurements of the rotational temperature of nitrogen and its concentration in front of a spherically blunt cylinder situated on the axis of a supersonic rarefied jet of nitrogen and nitrogen-hydrogen mixture.
TL;DR: In this paper, the expansion isentropes of the explosion products of two TNT/RDX compositions (50/50 and 25/75) have been investigated, focusing on the little-studied region of pressures below 100 kbars.
Abstract: The expansion isentropes of the explosion products of two TNT/RDX compositions (50/50 and 25/75) have been investigated. Attention is concentrated on the little-studied region of pressures below 100 kbars. Data on the expansion isentropes were obtained by measuring the shock wave parameters in various media (aluminum, plexiglas, polystyrene foam, argon, air). Points were obtained on the shock Hugoniots of argon precom-pressed to 10, 15, and 50 atm. An equation of state of the explosion products that satisfactorily describes the experimental material obtained is formulated.
TL;DR: In this article, the authors used collapsing air gap to investigate the development and limiting parameters of the Mach reflection of a conical convergent shock in plexiglas cylinders arranged along the axis of a detonating explosive charge.
Abstract: The “collapsing air gap” method has been used to investigate the development and limiting parameters of the Mach reflection of a conical convergent shock in plexiglas cylinders arranged along the axis of a detonating explosive charge. The diameters of the cylindrical specimens varied from 15 to 100 mm. It is shown that on the stationary interval of development of the triple-shock configuration, where the velocity of the head wave is equal to the detonation velocity, there is a linear relationship between the diameter of the head wave, its radius of curvature, and the diameter of the cylinder.
TL;DR: In this paper, the wave velocity-particle velocity relations for polystyrene of normal and reduced density together with the shock Hugoniots are given for the entire set of experimental data.
Abstract: The dynamic compressibility of polystyrene [C6H5-CH-CH2]n with initial densities of 1.0, 0.7, 0.5, and 0.3 g/cm3 has been investigated at pressures of 200–400 kbars. The D−ρ0 (wave velocity-initial density) relations are presented for specimens of normal and reduced density tested under identical conditions. Wave velocity-particle velocity relations are given for polystyrene of normal and reduced density together with the shock Hugoniots. The simplest equation of state satisfactorily describing the entire set of experimental data is selected.
TL;DR: In this article, it is assumed that the dynamic stress-strain diagram is largely insensitive to the rate over a certain range, and the best that experiment can then do is to confirm or reject some prior assumptions.
Abstract: Stress-strain relationships for metals at high strain rates have long been studied, but no really reliable and generally accepted theory has emerged. It is sometimes assumed that the dynamic stress-strain diagram is largely insensitive to the rate over a certain range. Another approach is to insert derivatives of the stress and strata with respect to time. One difficulty in establishing the actual reIationships is that experiment provides only indirect evidence (direct tests are usually impossible). Any real dynamic experiment tends to produce complicated effects, which can be interpreted only if the basic equations are taken as known. The best that experiment can then do is to confirm or reject some prior assumptions.
TL;DR: In this paper, Schneide et al. introduced the concept of Fatigue Factor, which is a measure of the amount of fatigue consumed by a population in the United States.
Abstract: A l a r g e p r o p o r t i o n of f a i l u r e s of mach ine p a r t s is a s s o c i a t e d with the p ropaga t i on of fa t igue c r a c k s . In such c a s e s the " l i fe" of a p a r t counted f rom the ins tan t of c r a c k nuc lea t ion cons t i tu tes a c o n s i d e r a b l e p a r t of i t s total t i m e t o r u p t u r e . Fa t igue f r a c t u r e , which in the USA alone is be ing inves t iga ted in m o r e than 209 l a b o r a t o r i e s , has been s tud ied by many i n v e s t i g a t o r s both in the Soviet Union (N. N. Davidenkov, S. V. Se rensen , I. A. Oding, R. M. Schneide rov i ch , R. D. Vagapov) and e l s e w h e r e (Orowan, F r o s t , McClintock, P a r i s ) . However , insuf f ic ien t a t ten t ion has been paid to quant i ta t ive s tud ies of the growth of fat igue c r a c k s .
TL;DR: In this article, a set of pipes are connected to a p r iming and evacuating unit by a series of pipes and a polished plunger is sealed in the lower par t of the socket by a teflon gland.
Abstract: A d iag ram of the exper imenta l setup is shown in Fig. 1. Capi l la r ies 1 and 2 a re inse r ted in tubes 4 and 5 of cy l inder 3 which is held in s leeve 7 attached to socket 8. The sleeve is connected to a p r iming and evacuating unit by a set of pipes . The third capi l la ry 6 is intended for record ing the beginning and end of a working cycle . The polished plunger 9 is sealed in the lower par t of the socket by a teflon gland. The whole is mounted on the heavy bottom plate 10 of the rmos ta te 17 of 15-I capacity. High t e m p e r a t u r e s a re produced by two hea te r s of 700 and 1300 W, respec t ive ly , and low ones by means of an FAK-0.7M r e f r i g e r a t o r 18.