Analysis of the Applicability of Macroscopic Models of the Shock Wave Structure in a Binary Mixture of Inert Gases

The results of calculating the shock wave structure in Ne–Ar, He–Ar, He–Ne, and He–Xe mixtures by means of the relaxation method on the basis of the system of Navier-Stokes equations and complete and modified systems of Burnett equations are compared with the results of direct statistical simulation (Monte-Carlo method). The domain of applicability of these systems of equations for calculating gas dynamic variable profiles is analyzed as a function of both the molecular mass ratio and the initialconcentrations.     

Pairwise nonlinear interactions of tollmien-schlichting waves in flows of the boundary-layer type

For a flow of the boundary-layer type, the method of a phase plane is used to investigate the joint evolution of a pair of Tollmien–Schlichting waves as a function of the R numbers and the frequencies.Translated from Izvestiya Akademii Nauk SSSR, Mekhanika Zhidkosti i Gaza, No. 2, pp. 33–37, March–April, 1977.     

Interaction between the boundary layer and a supersonic flow when part of the wall is rapidly heated

There have been many theoretical studies of aspects of the unsteady interaction of an exterior inviscid flow with a boundary layer [1–9]. The mathematical flow models obtained in these studies by the method of matched asymptotic expansions describe a wide range of phenomena observed experimentally. These include boundary layer separation near the hinge of a flap, the flow in the neighborhood of the trailing edge of an oscillating airfoil [1–2], and the development and propagation of perturbations in a boundary layer excited by an oscillating wall or some other way [3–5]. The present paper studies the interaction of an unsteady boundary layer with a supersonic flow when a small part of the surface of a body in the flow is rapidly heated.Translated from Izvestiya Akademii Nauk SSSR, Mekhanika Zhidkosti i Gaza, No. 1, pp. 66–70, January–February, 1984.     

Effect of anisotropy of the medium on the stresses on the surface of a crack

Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, No. 6, pp. 121–126, November–December, 1992.     

Characterisation of non-linear viscoelastic foods by the indentation technique

A method to determine the non-linear viscoelastic constitutive constants from indentation force–displacement data corresponding to different indentation speeds has been developed. The method consists of two parts. In the first part, the force–displacement data is expressed as two functions which represent the strain and the time-dependent responses, respectively. From these functions, the time-dependent constants and the instantaneous force–displacement response are obtained. In the second part, the strain-dependent variables are determined from the instantaneous force–displacement response through an inverse analysis based on the Levenberg–Marquardt method. The method was verified by numerical experiments using the properties of cheese as examples.     

Conservation of the resultant force vector in the plane of the angle of attack for slender star-shaped bodies in supersonic flows

At high supersonic flight speeds bodies with a star-shaped transverse and power-law longitudinal contour are optimal from the standpoint of wave drag [1–3]. In most of the subsequent experimental [4–6] and theoretical [6–9] studies only conical star-shaped bodies have been considered. For these bodies in certain flow regimes ascent of the Ferri point has been noted [10]. In [11] the boundary-value problem for elongated star-shaped bodies with a power-law longitudinal contour was solved for the case of supersonic flow. The present paper deals with the flow past these bodies at an angle of attack. It is found that for arbitrary star-shaped bodies with any longitudinal (in particular, conical) profile the aerodynamic forces can be reduced to a wave drag and a lift force, the lateral force on these bodies being equal to zero for any position of the transverse contour.Translated from Izvestiya Akademii Nauk SSSR, Mekhanika Zhidkosti i Gaza, No. 6, pp. 135–141, November–December, 1989.     

Identification of the Ten Inertia Parameters of a Rigid Body

Standard experiments for identifying inertia parameters of a rigid body only provide a subset of the inertia parameters of the body [1–10]. In addition, they do not use in the estimation process the complete information included in the equations of motion of the rigid test body. The objective of the work described in this paper is the simultaneous, automatic experimental identification of the ten inertia parameters of a rigid body using the complete information hidden in the nonlinear model equations of the test body. This task has been solved in several steps:– mathematical modelling of the special motions of a rigid body in space. These model equations have been mapped into a form suitable for identification purposes (identification hypothesis)– design of a special measurement robot for performing the identification experiments– laboratory experiments providing test data used for the identification experiments– identification of the inertia parameters and accuracy tests.The accuracy of the identified parameters is satisfactory.     

Refinement of the relations of the Kol'skii-Hopkinson compound-rod method

Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, No. 3, pp. 127–131, May–June, 1992.     

Application of the Density-Functional Method for Numerical Simulation of Flows of Multispecies Multiphase Mixtures

Numerical examples of application of the density functional used to describe isothermal flows of two-phase two-species mixtures are given. The following flows are calculated in a two-dimensional formulation: impact of a drop on a liquid layer, breakdown of a drop in the velocity field of the Couette flow, formation of the wetting angle of a drop on a solid surface, and development of the Rayleigh–Taylor and Kelvin–Helmholtz instabilities at the gas–liquid interface.     

Determination of the edge-effect zone with the help of the holographic MoirÉ method

In parts made from materials with a distinct anisotropy, it is necessary to take into account edge effects which, as is well known [1], can slowly decay away from the edge. The size of the edge-effect zone in composite materials has been estimated many times and, in addition, the problem has been solved theoretically and experimentally [1–3]. In this work such estimates are made with the help of the method of holographic interferometry.Translated from Zhurnal Prikladnoi Mekhaniki i Tekhnicheskoi Fiziki, No. 5, pp. 132–135, September–October, 1986.     

Modeling the process of melt solidification on the surface of a material

Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, No. 2, pp. 122–126, March–April, 1992.     

Experimental investigation of the separation of flow around a sphere

The results of an experimental investigation of the flow around a sphere over a broad range of Mach numbers M=0.3–3 and Reynolds numbers Re=3·10⁴–3·10⁷ are presented. The experiments were carried out on a ballistic test stand and in a wind tunnel. Flow patterns and pressure distributions were obtained. In particular, the effect of the Mach and Reynolds numbers on the position of the separation point and the edge shock was studied; the pressure distribution on the sphere was measured; and a nonmonotonic displacement of the flow separation point upon passage through the speed of sound was established.Translated from Izvestiya Akademii Nauk SSSR, Mekhanika Zhidkosti i Gaza, No. 1, pp. 152–156, January–February, 1991.     

Exact solutions of the problem of the motion of the interface between immiscible fluids in a porous medium

Translated from Zhurnal Prikladnoi Mekhaniki i Tekhnicheskoi Fiziki, No. 1, pp. 68–71, January–February, 1991.     

Asymptote of the navier-stokes equation solution in the vicinity of a boundary angle

Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, No. 6, pp. 38–40, November–December, 1992.     

Localized Coherent Structures in the Boundary Layer

A Blasius laminar boundary layer and a steady turbulent boundary layer on a flat plate in an incompressible fluid are considered. The spectral characteristics of the Tollmien—Schlichting (TS) and Squire waves are numerically determined in a wide range of Reynolds numbers. Based on the spectral characteristics, relations determining the three–wave resonance of TS waves are studied. It is shown that the three–wave resonance is responsible for the appearance of a continuous low–frequency spectrum in the laminar region of the boundary layer. The spectral characteristics allow one to obtain quantities that enter the equations of dynamics of localized perturbations. By analogy with the laminar boundary layer, the three–wave resonance of TS waves in a turbulent boundary layer is considered.     

Optimization of the internal source in the problem of mhd flow around a sphere

Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, No. 3, pp. 30–38, May–June, 1992.     

Closure of the equations of turbulence using the analytic and scaling properties of the spectral functions

Translated from Prikladnaya Mekahnika i Tekhnicheskaya Fizika, No. 6, pp. 83–93, November–December, 1991.     

Non-linear dynamics of a drill-string with uncertain model of the bit–rock interaction

The drill-string dynamics is difficult to predict due to the non-linearities and uncertainties involved in the problem. In this paper a stochastic computational model is proposed to model uncertainties in the bit–rock interaction model. To do so, a new strategy that uses the non-parametric probabilistic approach is developed to take into account model uncertainties in the bit–rock non-linear interaction model. The mean model considers the main forces applied to the column such as the bit–rock interaction, the fluid–structure interaction and the impact forces. The non-linear Timoshenko beam theory is used and the non-linear dynamical equations are discretized by means of the finite element method.     

Stability of the motion of metal plates driven by the grazing detonation of a flat charge

Translated from Zhurnal Prikladnoi Mekhaniki i Tekhnicheskoi Fiziki, No. 2, pp. 162–165, March–April, 1991.     

Nonstationary waves in the continuously stratified flow of a fluid of finite depth

A theoretical investigation is made of the development of linear two-dimensional waves in a continuously stratified flow of an ideal incompressible fluid. The waves are generated by pressures that are independent of time and that are applied at time t=0 to a bounded region on the free surface of an initially undisturbed flow. The stationary internal waves generated by such a disturbance have been investigated in [1–3]. The nonstationary waves in a continuously stratified fluid that are generated by initial disturbances or periodic surface pressures applied to the entire free surface have been studied in [4–7] in the absence of a slow.Translated from Izvestiya Akademii Nauk SSSR, Mekhanika Zhidkosti i Gaza, No. 6, pp. 87–93, November–December, 1976.