Stresses and strains on the surface of anisotropic inclusions in stochastic composites

Institute of Mechanics of the Ukrainian Academy of Sciences, Kiev. Translated from Prikladnaya Mekhanika, Vol. 26, No. 6, pp. 13–19, June, 1990.     

Quantum linguistic statistics

Formulas specifying the Zipf law for frequency dictionaries are presented. Principles from which these formulas follow are discussed.     

Aerodynamic characteristics of a delta wing in hypersonic flow

Novosibirsk. Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, No. 2, pp. 66–69, March–April, 1994.     

Wave‐field structure in active bubble systems in shock tubes with “discontinuities” in cross section

The wave structure in active bubble media in shock tubes with sudden changes of profiles in the form of discontinuities in cross section and a onephase liquid waveguide is analyzed numerically. In axisymmetric formulation, the paper studies wave amplification due to reflection from a wall and focusing at the buttend of a rigid rod aligned coaxially with the channel. In this configuration, the amplification effect results from twodimensional cumulation of the shock wave after it leaves the annular channel and reaches the buttend of the rod. A Mach configuration forms in the focus spot. The geometrical characteristics of the shock tube allow one to control (to some extent) the amplification coefficient and the coordinates of the focus spot. In particular, it is shown that the wave can be focused near the second discontinuity of cross section — a rigid wall (in the region of passage through the interface to the waveguide) — and intensified upon reflection. If the waveguide radius is equal to the height of the Mach stem, the reflected wave has a maximum amplitude.     

Elastic properties of obliquely wound composites with a damaged matrix

Special Design and Technological Office, Institute of Mechanics, Academy of Sciences of Sciences of the Ukrainian SSR, Kiev. Translated from Prikladnaya Mekhanika, Vol. 25, No. 2, pp. 82–89, February, 1989.     

Numerical solution to the problem of the complete stabilization of a supersonic boundary layer

A method is suggested for solving numerically the problem of the complete stabilization of a supersonic boundary layer. It is shown that when the surface is significantly cooled, the neutral stability curve splits into two branches. A calculation is given for the temperatures of complete stabilization for both neutral curves. A comparison of the results obtained with those derived from asymptotic calculations shows that above M = 2 (M is the Mach number) the asymptotic method gives incorrect results.Translated from Zhurnal Prikladnoi Mekhaniki i Tekhnicheskoi Fiziki, No. 2, pp. 39–43, March–April, 1972.     

Experimental study of stability of strongly underexpanded laminar free and impact jets

The growth rates of density fluctuations in the mixing layer of strongly underexpanded lowdensity jets are measured by the electronbeam technique within the range of Reynolds numbers Re_L = 50 – 230. Regimes of selfinduced oscillations are determined for these flow conditions in the case of a jet incident normally onto a finitesize target. Results on the frequency of pressure oscillations on the target are obtained and compared with the spectra of the growth rates of density fluctuations in the mixing layer of free jets. It is shown that selfinduced oscillations cannot be sustained because of the development of instability in the mixing layer of the jet.     

Computation of the pressure on the surface of a fuselage with a wing in an ideal fluid

The flows around complex three-dimensional bodies by an ideal fluid are computed by methods [1–3] using approximation of the surface by a set of plane elements. A layer of surface singularities, whose intensity is found by solving a system of linear algebraic equations of very high order, is distributed continuously over each element. Evaluation of the system coefficients and its solution require significant machine time expenditures on powerful electronic computers. If in the method of [2] the total system of equations is separated successfully into several subsystems by simplifications and an approximate solution of the problem is obtained more rapidly than by the method in [1], then the same author practically used the method in [1] to design specific fuselages in [3]. A method [4] developed for a fuselage is expanded in this paper to design a wing-fuselage combination. This method turns out to be less tedious, without being inferior in accuracy, by being different from the method in [1] in the means of solving the fundamental integral equation.Translated from Izvestiya Akademii Nauk SSSR, Mekhanika Zhidkosti i Gaza, No. 3, pp. 110–115, May–June, 1977.     

A homogeneous gas mixture

We obtain relations for critical values of the mixture of new ideal gases and write differential equations for the mixture of real gases.