Home – Home – Jornals – Thermophysics and Aeromechanics 2004 number 2

Results of numerical and experimental investigations of supersonic flow regimes around a delta wing with a sweep angle of 78^o for a Mach number of 2.75 and angles of attack of 6, 8, 18, and 20^o are described. The computations are performed within the framework of three-dimensional Euler equations with a zonal approach. A comparative analysis of results of numerical and physical experiments and verification of the numerical model developed are performed. It is shown that the computation method allows adequate simulation of the basic specific gas-dynamic features of the flow past the leeward side of the delta wing.

The generation of 3D Tollmien

The problem of the computation of the slip velocity of a rarefied gas over a solid spherical surface has been solved by exact analytic methods. The drag force acting on a sphere slowly moving in rarefied gas has been determined. A comparison with the data available in the literature has been performed.

The effect of the choice in central jet feeding method and radial displacement of the outlet opening on gas dynamic and turbulent characteristics of gas flow in a vortex chamber was studied experimentally. The two-component laser Doppler anemometer was used in experiments. The flow rotation axis follows the displacement of the axis for outlet diaphragm. While that, the maximum of circumferential velocity decreases as the outlet opening is shifted away from the chamber axis. For a high shift, the flow swirling decreases drastically. The maximum of longitudinal velocity always remains in the near-axis zone of chamber and almost independent of the radial shift of exhaust diaphragm. Application of different techniques for feeding of an axial no swirling jet demonstrated that the average profiles of axial and circumferential velocities are self-similar. The changes in turbulence degree evidenced about qualitative resemblance of Tu distributions for all considered options for axial jet. The result is that a positive radial gradient of circulation in the middle area suppresses the turbulence as the flow travels from the inlet to the outlet. The measurement results for average velocity and turbulence degree in the face-end boundary layer are presented.

The system of equations obtained previously for the conditions of the transformation of differential equations of convective heat and mass transfer of a stationary three-dimensional boundary layer into the equations of low-speed flows, including the quasi-isothermal and quasi-homogeneous flow, is generalized and analyzed. The equations are considered: the conditions, the boundary requirements, and transformation functions, the classes and subclasses are identified, including a closed subclass of the two-dimensional transformation.

The microprocesses of the nanoparticles interaction with a condensed solvent are investigated and simulated by the molecular dynamics method. It is shown that the autocorrelation function of random force acting on a particle from the medium contains besides customary-correlated term also the exponential contribution. The space-time correlation function of the response of the medium velocity field to particles motion is calculated. The peculiarities of the behavior of this function in systems with various parameters are investigated. The perturbation wave spreading with sound speed from moving nanoparticle is registered. For massive nanoparticles the presence of the second maximum of the correlation function is revealed.

A system of differential equations and boundary conditions for nonstationary heat and mass transfer in porous media taking into account the work done by the surface forces at the interfaces between the phases is proposed. The system is based on the laws of mass and energy conservation for each of the phases, on the basic concepts of the classical theory of two-phase filtration, on the Kelvin formula, on the Clapeyron

Results of experimental study of gas-liquid slug flow in a vertical tube are presented. The electrochemical method was used for measurements. The method of conditional averaging of the studied parameters by ensemble of realizations was worked through. Velocity distribution was measured for various flow regimes of a gas-liquid mixture using this method. Distributions of liquid velocity in a liquid plug were obtained depending on a distance from the plug beginning. It is shown that within the initial region of a liquid plug, profiles of liquid velocity are deformed significantly in comparison with the velocity profile in a single-phase flow, and this is caused by the effect of a toroidal vortex formed after a previous gas slug.

A numerical analysis of the tasks of displacement for one-dimensional case of the Muskat

Surface deformation of a liquid film falling over a vertical heated plate is being studied. The equation describing a change in film thickness was obtained in long-wave approximation with consideration of small surface perturbation. Approximated analytical solution for distribution of temperature within a film and surface perturbation was obtained for the case of weak heat transfer between liquid and gas and different thermal conditions. Dimensionless criteria determining surface deformation of a film were revealed and their effect on the solution obtained was analyzed.

The newly developed complex for remote diagnostics of combustion in natural conditions was applied for study of main modes of hydrocarbon gaseous fuel combustion. The main regularities of a change in flame emission intensity and concentration of hydrogen/oxygen concentration as a function of fuel mixture content were obtained for flames without mutual interference. This knowledge was the basis for development of algorithms for identification of the current combustion mode and procedures aimed at optimization of operation of a standard heating boiler DE 24/15. The efficiency of these procedures was demonstrated. This approach can be used after additional study for control of heating boilers of any type.

Some methodical aspects for formulating boundary conditions and their connection with potential theory are analyzed in the article with reference to differential and integral equations of radiation.

Physical processes of mass transfer intensification by shock waves were considered for a three-phase medium comprising liquid, gas bubbles, and soluble particles. The estimates for mass transfer coefficient were obtained.

The coefficient for a rotating bubbling layer friction against the face ends of vortex chamber was measured.

Vladimir Vasilievich Struminsky was born on April 29, 1914. Academician Struminsky was the head of the Institute of Theoretical and Applied Mechanics SB USSR AS, the Chair of gas dynamics of the Novosibirsk State University in 1966