Home – Home – Jornals – Thermophysics and Aeromechanics 2003 number 1

The formation and development of coherent vortical structures at the late stages of the laminar-turbulent transition initiated by a harmonic, almost two-dimensional Tollmien – Schlichting (TS) wave in a self-similar boundary layer with Hartree parameter β_H=

Investigation results of a linear and nonlinear development of the travelling secondary disturbances on streamwise structures in a swept wing boundary layer are presented, and peculiarities of a laminar-turbulent transition at a nonlinear development regime of the travelling disturbances are reported.

The evolution of natural disturbances in a flat-plate boundary layer is experimentally studied for a Mach number M = 2. To obtain a more detailed pattern of transition in the boundary layer, the measurements are performed both in the longitudinal and normal coordinates. The development of oscillations is analyzed using a statistical approach. It is found that the growth of natural oscillations is linear up to a Reynolds number Re_δ = 1100. The amplitude of oscillations at the final stage of linear development of disturbances is approximately 4 %.

An analogy was established between the streamlining of blades in the Darrieus wind turbine and unsteady flow around a flapping wing. New results were established for Darrieus turbine: possibility of self-start, and new efficient method for aerodynamic limitation of rotation speed.

The reasoning for the advisability of using the classical Prandtl

A theoretical study is given to a spatial-temporal development of a spherical glow discharge of low pressure using the self-consistent hydrodynamic approximation. The model includes non-stationary continuity equations for electrons and ions in a drift-diffusion approximation and the Poisson equation for radial electric field. The system of equations was solved by relaxation method for the entire inter-electrode gap using an implicit numerical scheme. The result is a time-developing pattern of spherical discharge. In calculation of stationary distributions, the Ohm law was used as a feedback between the discharge voltage and the current. It was demonstrated that for the spherical discharge, as distinct from a tube discharge, the condition of quasi-neutrality is not valid for the entire zone from the anode to cathode.

Investigation results of a bubbly gas-liquid flow in an inclined rectangular channel are presented. The angle of channel inclination was varied from vertical to horizontal. Profiles of velocity, local void fraction, and wall shear stress were measured using the electrodiffusional method. A strong effect of the channel inclination on flow parameters was determined. Maximal shear stress on a wall and deformation of the liquid velocity profile were observed over the range of channel inclination angle of 30 50?. Profiles of liquid velocity were calculated using the work by Sato et al. (1981). Sato

Results of numerical simulation of heat and mass transfer process in a low-temperature heat pipe with two local sites of heat release are presented. Distributions of hydrodynamic and thermodynamic parameters are obtained.

The method for determination of boundary conditions at the interface between two media with different refraction indexes is presented in application to exact and approximate approaches for calculation of radiant heat transfer.

The analytic form for the representation of radiation configuration factors of internal surface of infinite spiral is studied with regard for peculiarities of axisymmetric radiating systems and the part of radiant energy

The heat capacity of the composite material TiC

The method of chain analogy was used to analyse the electric parameters of a high-frequency hybrid plasmatorch of decreased pressure which works in a weakly-pumping regime. The results of this analysis performed in one-electron approximation are in a good agreement with the experiment, allow to formulate a number of requirements for the active element basis of high-frequency generators.

An approach is proposed for optimizing the parameters of thermal power and power technology installations with regard for a random character of the input data, which is based on accepting the efficiency criterion with a given level of security as the objective function. The algorithm for solving the problem under study is presented. The approach is illustrated by the example of optimization of the power technology installation for methanol catalyst synthesis and electric power production.

The scheme is given for calculation of plasma-coal lighting of flame: it includes calculation of heat effect from plasma-coal lighting, different designs of plasma-coal burner and feeding conditions of the coal dust mixture, and calculation of optimal concentration of coal in the air-coal mixture.