Deformation of the Surface of a Conducting Liquid under the Action of a Pulse of a Strong Field

It has been shown that the development of the process of the so-called Frenkel–Tonks instability occurring in the case of application of an electric field to a plane surface of a conducting liquid is also determined by the size of the initial distortions of the surface.     

Influence of the temperature of a flow on the readings of a hot-wire anemometer

The error due to the flow temperature and sensor wire temperature in measuring the mean velocity of a flow using a hot-wire anemometer is studied.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 49, No. 3, pp. 366–374, September, 1985.     

Algorithms for the Optimum Estimation of the Parameters of a Radio Signal in a Measurement Time of Less Than a Period and a Nonmultiple of a Period in Which the Result Is Tied to the Beginning of the Measurement Interval

Optimum estimates of the parameters of a noisy (white noise) sinusoidal radio signal of known frequency are considered, based on an investigation of the likelihood function, when the measurement time is less than a period and a nonmultiple of a period. Estimates are presented for the phase shift and the amplitude in the presence (absence) of a constant component and nonlinear distortions when the result is tied to the beginning of the measurement interval.     

On the absorption of a surface acoustic wave in a bulk superconductor in the presence of a supercurrent

Surface acoustic wave absorption in bulk superconductors in the current state at low temperatures is discussed. In this situation a group of quasiparticles are localized near the surface due to the inhomogeneous supercurrent distribution; the rest of the quasiparticles have infinite trajectories. It is shown that it is possible for the main contribution to the acoustic wave absorption to be due to this group, depending on the sonic frequency. If this frequency is large, the localized quasiparticles are the most important in the absorption. In this case the absorption coefficient can be larger than in the absence of the supercurrent. In addition, there is a dependence of the absorption on the angle between the directions of the acoustic wave propagation and of the supercurrent. In the case of lower acoustic frequency, the quasiparticles with infinite trajectories dominate in the absorption. In this situation the absorption coefficient is smaller than in the zero-current state, because of the Andreev reflection of a fraction of these quasiparticles. It is shown that by studying the absorption dependence on the direction and on the absolute value of the current it is possible to obtain information on the law of current decrease near the surface of the sample, on the angular dependence of the deformational potential tensor, etc.     

Evaluation of the Field near a Cusp of a Caustic

The field in the neighbourhood of a cusp of a caustic can be expressed in terms of a function of two variables, P(X,Y), known as Pearcey's integral or the Pearcey function. In this paper we develop efficient algorithms for computing this function and its derivatives P/ X and P/ Y. They are based on a Taylor series expansion in a region close to the cusp at X = Y = 0, and on asymptotic approximations in regions far from the cusp. The asymptotic results are given in terms of contributions of isolated stationary points in regions far from the caustic, and in terms of the Airy integral function and its derivative in a region close to the caustic. Three terms in the asymptotic expansions are used, and they give an accuracy for P(X,Y) better than 0·006 in amplitude and 0·6° in phase at distances from the cusp greater than (X² +Y² )^1/2 = 4.     

Toward the problem of the resonances of a bubble radially pulsating in a liquid

Gas bubbles performing radial pulsations under the action of an acoustic field are analyzed. It is shown in detail that gas bubbles of constant mass may have only one resonance frequency.     

On the effects of a crack propagating toward the interface of a bimaterial system

This paper deals with the influence of matrix cracks on the failure mode of bimaterial systems and composite materials. In order to investigate such an influence, the stress field near a crack embedded into the more yielding material and propagating perpendicularly to the interface, has been analyzed by using systematic numerical simulations. Such analysis has shown that the crack propagation give rises to transversal stresses that can damage the reinforcing materials when this has low modulus, as glass fibers, or low transversal strength, such as carbon fibers. Moreover, the longitudinal stress concentration can damage the reinforcing material only if this has high stiffness, as in the case of aramid and carbon fibers.Also, the numerical results have permitted to implement simple formulas that allows the user an accurate evaluation of the SIF as well as to predict possible debonding or fiber splitting phenomena. Finally, the SIFs evaluated numerically have been corroborated by experimental tests carried out by using an efficient procedure based on RGB digital photoelasticity.     

Effect of the pulsations of a liquid on the averaged motion of a suspended particle

It is shown that particles moving in a pulsating flow with relative velocities extending outside the normal Stokes range acquire average velocities differing from those normally associated with sedimentation.Deceased.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 19, No. 5, pp. 837–843, November, 1970.     

Development of a flow field structure in the vicinity of a circular cylinder in the presence of a laminar-turbulent transition

The Reynolds equations and the two-parameter differentialq-Ω model of turbulence are used to investigate a flow past a circular cylinder with an isothermal surface (temperature factorT _w0 = 0.5) at the Mach numberM _∞ = 5 in the range of Reynolds numbers Re = 10⁴-10⁸. It is demonstrated that the turbulization of flow leads to a shift of the separation point downstream, a reduction and stabilization of the separation zone length, a decrease in the maximum velocity in the separation zone, and an increase in the heat flux at the rear stagnation point compared with its value at the forward stagnation point.     

The Effect of a Heat Source on the Adiabatic Heating of a Fluid in the Vicinity of a Critical Point

For a fluid with near-critical parameters, the adiabatic heating referred to as the piston effect arising as a result of compression is investigated. The heating from a source of constant power is treated. One-dimensional analysis and numerical simulation of the effect are performed, and a comparison is made with a similar process developing from a source of constant temperature. It is found that, as the critical point is approached, the piston effect of the type under consideration ceases to depend on the parameters of the fluid, this qualitatively differing from the effect triggered by an isothermal source.     

Experimental Investigation of the Decomposition of a Nonpolar-Gas Hydrate in a Pipe Under the Action of a Microwave Electromagnetic Field

Results of experimental investigations of the decomposition of a propane hydrate in a pipe under the action of a microwave electromagnetic field are presented. Methods of obtaining a gas hydrate, its decomposition under the action of a microwave electromagnetic field, and measuring the temperature and pressure in a pipeline have been developed. It has been established that the rate of decomposition of a gas hydrate increases under the action of a microwave electromagnetic field. It is shown that a gas hydrate in a pipe can be completely decomposed under the action of a microwave electromagnetic radiation whose wavelength is comparable to the thickness of this hydrate. __________ Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 78, No. 3, pp. 108–114, May–June, 2005.     

Interval Estimation of the Parameters of a Distribution from a Sample of a Random Quantity

A program is developed for solving the problem of making an interval estimation of the parameters of a distribution from a single sample of a random quantity, based on a statistical modeling method. The results of a solution of the problem for certain symmetric and asymmetric distributions are presented. The average error in estimating the confidence intervals and their limits is 4–15% in the range of values of the confidence level of 0.8 P 0.998 for a sample volume of N = 500–1000.