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Laboratory experiments with a first-overtone CO laser are performed to simulate a lidar system. The trace remote sensing scheme of atmospheric gases (nitrous oxide and methane) at emission lines of the pulsed first-overtone CO laser is tested using topographic target and receiving telescope. Results of the measurements of absorption of the first-overtone CO laser operating at 20 selected emission lines in gas mixtures with the gases studied at various configurations of the experimental scheme are presented.

To reconstruct the data of hydrophysical parameter observations, a model based on a neural network with the teacher has been suggested. The indices of global climate modes of the ocean-atmosphere system were applied as the model input. The processes of the model teaching and adaptation, which allow one to find the most accurate solution of the problem of modeling, is described. The comparison of modeled monthly average Danube's runoff with data of observation demonstrated their good correspondence. Missed in some years observation data on sea water transparency (depth of white disc visibility) were reconstructed. The proximity of reconstructed and observed depths of white disc visibility was noted. Some features of interannual variability of reconstructed data on sea water transparency caused by both climatic factors during 1950-1962 and changes in the chlorophyll а concentration during 1998-2010 were found.

The methodological issues and theoretical results related to determination of the boundaries of laser-hazard distances (LHD) when eyes are exposed to direct and scattered radiation produced by a laser landing system (LLS) are discussed. LHD calculation algorithms during LLS operation in field conditions are considered. LHD have been calculated for a single and a group of laser sources for a variety of weather conditions. Computer software for laser radiation dosimetry calculation during LLS operation in field conditions is suggested.

LDA and PIV techniques were used to study the decay of an axisymmetrical turbulent wake originated downstream an immobile disk in a water flume for Reynolds numbers Re = 1.5-2.4×10⁵. Data were compared with experiments performed with a set of thermo-anemometers behind a disk in a wind tunnel at lower Reynolds numbers (Re = 1.3-2.6×10⁴).
Observations for a new range of Reynolds number confirmed that the velocity distribution in the disk wake keeps self-similarity. The decay of a wake by the power law -2/3 in the presented experiments remains until the maximum deficit of velocity becomes comparable with the turbulent pulsation level in the free-stream (less than 2 %).

The gas dynamics of a supersonic radial jet was studied under conditions close to cold spraying. The jet visualization was performed for exhaustion into submerged space with atmospheric pressure and jet impingement to a target. For the cases of swirled and unswirled supersonic radial jets, the pressure profiles measured by a Pitot tube were taken for different distances from the nozzle outlet and for different widths of supersonic part δ_ex = 0.5–2 mm and for prechamber pressure in the range p₀ = 1–2.5 MPa.

In the present paper, we consider one of the most efficient and simple methods to additionally intensify the exchange processes and heat transfer in the separated flow behind a backward-facing step. The method uses small obstacles installed upstream the step; such obstacle act as turbulators smaller in size than the main obstacle. As the turbulators, solid mini ribs, comb ribbings, and wall-detached mini ribs were used. Intensification of the turbulent mixing process behind the main obstacle occurs due to the introduction of small-obstacle-induced 2D and 3D perturbations into the separated shear layer behind the step. Results of a detailed experimental study of the distributions of pressure and heat transfer for different heights of the small intensifier and its positions with respect to the step are reported. The influence of intensifier shape on the thermal and dynamic characteristics of the flow has been analyzed. The distributions of pressure and heat-transfer coefficients were used to evaluate the effectiveness of the various mini ob-stacles and the limits of their action on the drag and heat transfer.

The flow in the separation region of laminar boundary layer behind a rectangular backward-facing step has been experimentally examined under temperature non-uniformity of the flow. The data were obtained in a subsonic wind tunnel at Reynolds numbers M << 1. The temperature disturbance was generated using a system of Peltier elements provided on the model surface upstream of the separation line. The effect of heating/cooling of the wall on the mean and fluctuating flow components was evaluated using hot-wire measurements. The experimental data were supplemented with calculations of linear-stability characteristics of model velocity profiles in the separated boundary layer. As a result, the response of the separated flow to a stationary thermal perturbation was revealed.

Results of an experimental investigation of the temperature field across the liquid-gas two-layer system are presented. The liquid layer is locally heated from the bottom substrate, and the intensive liquid evaporation is observed. A technique for measuring the temperature profile across the liquid and gas layers (including their interface) is developed. To do these measurements, the microthermocouple is moved across the layers with the help of precision micropositioner with a step of 1 µm. The temperature jump at the liquid-gas interface is measured, and its value increases with the temperature increase. Detailed information on the temperature field near the interface is obtained by using the precise thermocouple displacement with a small step.

An experimental study of transient cooling in liquid nitrogen of strongly overheated copper plate coated with a low thermoconductive coating with thickness δ from 0.09 to 0.67 mm was performed. It is shown that the low thermoconductive coating has a significant effect on the character of temperature curves and total time of plate cooling. It was revealed that the most significant decrease in the time of plate cooling by the factor of 2.6 is achieved for the thickness of the low thermoconducting layer of 0.09 mm as compared to the case without coating.

The article presents the results of experimental investigation of boiling heat transfer of refrigerant R-21 in upward flow in a vertical plate-fin heat exchanger with transverse size of the channels that is smaller than the capil-lary constant. The heat transfer coefficients obtained in ranges of small mass velocities and low heat fluxes, which are typical of the industry, have been poorly studied yet. The characteristic patterns of the upward liquid-vapor flow in the heat exchanger channels and the regions of their existence are detected. The obtained data show a weak dependence of heat transfer coefficient on equilibrium vapor quality, mass flow rate, and heat flux density and do not correspond to calculations by the known heat transfer models. A possible reason for this behavior is a decisive influence of evaporation of thin liquid films on the heat transfer at low heat flux.