Stress tensor and energy flux in slow steady-state flow of a monatomic gas

On the basis of the linearized kinetic Choh-Uhlenbeck equation the stress tensor and energy flux are found in the gasdynamic approximation for steady states of a monatomic gas with allowance for the first virial correction to the transport coefficients. Moscow. Translated from Izvestiya Rossiiskoi Akademii Nauk, Mekhanika Zhidkosti i Gaza, No. 1, pp. 155–164, January–February, 1997.     

Reynolds analogy in a dusty laminar boundary layer

The nonisothermal Blasius problem for a gas suspension is considered on the basis of the equations of a quasiequilibrium two-phase laminar boundary layer [1–3]. Approximate analytical expressions are obtained for the friction and heat transfer coefficients and their region of applicability is estimated; the Reynolds analogy between friction and convective heat transfer processes [4] is extended to the case of a dusty quasiequilibrium laminar boundary layer. Translated from Izvestiya Akademii Nauk SSSR, Mekhanika Zhidkosti i Gaza, No. 6, pp. 160–162, November–December, 1986.     

Properties of solutions of a discrete Volterra system in a Banach space

We obtain a criterion for solutions of a linear discrete Volterra system with operator coefficients to be bounded or summable to a power p. __________ Translated from Neliniini Kolyvannya, Vol. 10, No. 2, pp. 184–187, April–June, 2007.     

Investigation of the heat transfer and Reynolds analogy in a turbulent boundary layer at a high freestream turbulence level

The results of a systematic experimental study of the flow turbulence level effect on the heat transfer and Reynolds analogy coefficients over a wide range of the relevant parameters (the turbulence intensity and scale and the Reynolds number) are presented. The notion of the equivalent flow turbulence, which unifies the above-mentioned parameters, is introduced. It is established that the skin friction and heat transfer coefficients increase with the equivalent turbulence, while the Reynolds analogy coefficient remains unchanged. Moscow. Translated from Izvestiya Rossiiskoi Akademii Nauk, Mekhanika Zhidkosti i Gaza, No. 1, pp. 61–71, January–February, 2000.     

Effect of streamwise structures on heat transfer in a hypersonic flow in a compression corner

Coefficients of heat transfer to the surface in a laminar hypersonic flow (M _∞ = 21) over plane and axisymmetric models with a compression corner are presented. These coefficients are measured by an infrared camera. The parameters varied in the experiments are the angle of the compression corner and the distance to the corner point. Characteristics of the flow with and without separation in the corner configuration are obtained. The measured results are compared with direct numerical simulations performed by solving the full unsteady Navier-Stokes equations. Experiments with controlled streamwise structures inserted into the flow are described. A substantial increase in the maximum values of the heat-transfer coefficient in the region of flow reattachment after developed laminar separation is demonstrated. __________ Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, Vol. 50, No. 4, pp. 112–120, July–August, 2009.     

Turbulent flow past a transverse cavity with inclined side walls. 2. Heat transfer

Convective heat transfer in a transverse cavity with a small aspect ratio, angle of wall inclination ϕ = 30–90°, and heated bottom, frontal, and rear walls of the cavity is studied experimentally. Temperature distributions are measured in longitudinal and transverse sections on three walls; temperature fields are measured over the entire heated surface. Local and mean heat-transfer coefficients are calculated. The highest intensification of heat transfer is found to occur on the rear wall for low values of ϕ Reconstruction of the one-cell structure to the two-cell structure of the primary vortex in the cavity leads to a drastic decrease in heat transfer over the cavity span from the end faces toward the center in the case with ϕ = 60 and 70°. A certain increase in the mean heat-transfer coefficient averaged over the entire heated surface is noted for ϕ = 60°. __________ Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, Vol. 48, No. 4, pp. 23–29, July–August, 2007.     

Effective Permeabilities in a Porous Medium with Log-Stable Statistics

Equations for the effective coefficients of random permeability fields for fluid flow through a porous medium with log-stable distributions are derived using the Wilson renormalization group approach. Results of the theoretical modeling are compared with data of numerical modeling. __________ Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, Vol. 46, No. 6, pp. 146–158, November–December, 2005.     

Design of a thin airfoil in a channel with permeable walls

A general solution is obtained for the boundary value problem of designing a thin airfoil in a channel with permeable walls from the given pressure distribution. A suitable choice of permeability coefficients makes it possible to construct a thin airfoil in a channel with impermeable walls, in a jet, etc. The effect of the wall permeability on the shape of the airfoil is studied. Cheboksary. Translated from Izvestiya Rossiiskoi Akademii Nauk, Mekhanika Zhidkosti i Gaza, No. 4, pp. 28–34, July–August, 1994.     

On the solvability of one class of problems of optimal control by coefficients in the principal part of a nonlinear elliptic operator

We consider the problem of the existence of solutions of an optimal-control problem for a nonlinear elliptic equation with Dirichlet conditions on the boundary in the case where the control functions are the coefficients in the principal part of the differential operator. It is shown that this problem has an optimal solutions in the class of generalized solenoidal matrices. Translated from Neliniini Kolyvannya, Vol. 12, No. 1, pp. 59–72, January–March, 2009.     

Experimental investigation of Marangoni condensation of ethanol–water mixture vapors on vertical tube

The heat transfer characteristics of the condensation of ethanol–water binary vapor on vertical tubes with the pipe diameter of 10 mm were investigated experimentally. The results showed that, with the change of the vapor-to-surface temperature difference, the condensation heat transfer coefficients revealed nonlinear characteristics with peak values under a wide variety of operating conditions. With the increasing pressure or velocity of the vapor, the heat transfer coefficients increased subsequently. The effect of vapor pressure or velocity on heat transfer coefficients reduced with the increasing ethanol mass fraction. It was noteworthy that, under low ethanol mass fractions (0.5–2%), the heat transfer coefficients augmented significantly, were about 5–8 times greater than that of pure steam. The comparison for different test blocks indicated that the condensation heat transfer coefficients for different pipe diameters were about the same value under the same operating condition. Significant heat transfer enhancement by Marangoni condensation could be achieved for full range of pipe diameter used in industrial condensers.     

Finite element analysis for train–track–bridge interaction system

This article deals with the dynamic analysis of train–track–bridge interaction system using the finite element method. In this interaction system, each four-wheelset vehicle in the train is modeled by a mass–spring–damper system with 10 degrees of freedom; the rails and the bridge decks are modeled as a number of Bernoulli–Euler beam elements, while the elasticity and damping properties of the rail bed are represented by continuous springs and dampers. The equation of motion for the interaction system is presented in matrix form with time-dependent coefficients. The correctness of the proposed procedure is illustrated by a comparison with the numerical result from the existing literature. Several numerical examples are chosen to investigate the effect of two types of vehicle models, two types of bridge models and three damping values of bridge on the maximum dynamic responses of train, track and bridges.     

Method of effective length for the boundary layer on a thin filament drawn out of a half-space

Heat transfer from a thin filament pulled from a half-space is considered. On the basis of the self-similar solution, obtained in the study, and using the method of effective length, the friction and heat transfer coefficients on the surface of a thin filament of varying radius and with distributed surface temperature and velocity are determined. The results obtained with this approximate method agree well with the results of a numerical solution of the boundary layer equations. Moscow. Translated from Izvestiya Rossiiskoi Akademii Nauk, Mekhanika Zhidkosti i Gaza, No. 1, pp. 23–28, January–February, 1994.     

Stability of convective flows in a rotating liquid layer under various heating conditions

For a rotating liquid layer with boundaries of low thermal conductivity, an amplitude equation is obtained that describes the evolution of secondary convective flows in uniform heating and above a hot spot. The dependence of the coefficients of the amplitude equation on the rotation parameter, Prandtl number, and heat-flux nonuniformity is obtained. The influence of rotation on the stability of nonlinear regimes is analyzed for uniform heating. The boundaries of flow stability are investigated for variously shaped hot spots. Perm'State University, Perm'614600. Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika. Vol. 39, No. 1, pp. 69–74, January–February, 1998.     

Instability of a plane interface between two immiscible conducting viscous fluids in a normal electrostatic field

The dispersion relation for motions of a charged plane interface between two viscous incompressible immiscible conducting fluids is analyzed numerically for finite values of all the parameters involved. It is shown that in addition to the well-known aperiodic (Tonkes-Frenkel’ type) instability for certain values of the physical parameters an oscillatory instability with periodically growing amplitude may be realized in the system. Yaroslavl’. Translated from Izvestiya Rossiiskoi Akademii Nauk, Mekhanika Zhidkosti i Gaza, No. 6, pp. 116–123, November–December, 1998.     

Construction of an asymptotic solution of the Cauchy problem for a degenerate linear system in the singular case

We propose an algorithm for the construction of an asymptotic solution of the Cauchy problem for a singularly perturbed linear system of differential equations with degenerate matrix of coefficients of derivatives in the case where the limit pencil of matrices is singular. __________ Translated from Neliniini Kolyvannya, Vol. 11, No. 2, pp. 271–288, April–June, 2008.     

Enhancing the controllability of a composite dielectric

The possibility of increasing the control coefficient of a nonlinear dielectric is studied. Composite structures are designed for which the control coefficient of the composite is considerably (5–20 times) higher than the control coefficients of its components are developed. __________ Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, Vol. 49, No. 5, pp. 143–152, September–October, 2008.     

Effect of pressure gradient of friction and heat transfer in a dusty boundary layer

Approximate analytic expressions for the local friction and heat transfer coefficients in a dusty laminar boundary layer are obtained and tested in the case of an incompressible carrier phase, power-law variation of the external gas flow velocity and small velocity and temperature phase disequilibrium. These expressions supplement the numerical analysis of the dusty boundary layer on a blunt body [1, 2] and the asymptotic calculation of the friction and heat transfer in a quasiequilibrium dusty gas boundary layer on a plate [3]. The combined effect of dustiness and pressure gradient on the friction and heat transfer coefficients is discussed. The results obtained can be used for the practical calculation of the friction and heat transfer in a quasiequilibrium dusty laminar boundary layer and for interpreting the corresponding experimental data. Tomsk. Translated from Izvestiya Akademii Nauk SSSR, Mekhanika Zhidkosti i Gaza, No. 5, pp. 105–108, September–October, 1988.     

On the universal aerodynamic relations following from the newtonian theory

A new, more general than that of [1], approach to the analysis of aerodynamic coefficients within the framework of the modified Newtonian theory is developed. Universal aerodynamic relations, similar to those of [1] but easily solvable with respect to the aerodynamic coefficients, are derived. Universal relations for the areas of the “windward“ zone projections onto planes normal to the axes of a Cartesian reference frame are obtained. Moscow. Translated from Izvestiya Rossiiskoi Akademii Nauk, Mekhanika Zhidkosti i Gaza, No. 6, pp. 149–152, November–December, 1998.     

Slip coefficients and macroparameter jumps of a diatomic gas with rotational degrees of freedom on a weakly curved spherical surface

Using the half-space moment method, the problem of the slip of a diatomic gas along a rigid spherical surface is solved within the framework of a model kinetic equation previously proposed which takes into account the rotational degrees of freedom of the gas. Second-order slip coefficients (correctionsC _m ^′ , β _R ^′ , and β _R to the isothermal and thermal slip which are linear with respect to the Knudsen number Kn) are obtained. The gas macroparameter jump coefficientsC _v andC _q, which are of the second order in the Knudsen number and characterize the discontinuity of the normal mass and heat fluxes on the gas-rigid phase interface, are calculated. These coefficients are given as functions of the tangential momentum accommodation coefficient, the translational and rotational energy accommodation coefficients, and the Prandtl number. The coefficients are calculated for certain diatomic gases. Moscow. Translated from Izvestiya Rossiiskoi Akademii Nauk, Mekhanika Zhidkosti i Gaza, No. 1, pp. 163–173, January–February, 2000.