Wind and turbulence profiles in a simulated wind tunnel boundary layer

A system of Honeycomb Flat Plate (HFP) grid and cylindrical rods has been developed to accelerate the growth of a thick (32 cm) turbulent boundary layer, artificially, over rough floor of a low speed short test-section (0.61 m x 0.61 m) wind tunnel. Simulated profiles of wind velocity, longitudinal turbulence intensity and Reynolds stress are shown to have similarity to those of a neutral atmospheric boundary layer over a typical rural terrain. Longitudinal spectrum of turbulence measured at 10,30 and 100 mm above tunnel floor is shown to compare well with atmospheric spectrum and agree closely with the Kolmogoroff's -2/3 law in the inertial sub-range of the spectrum. Based on the length scale of longitudinal turbulence estimated from the spectrum, a scale of 1 :900 has been proposed for laboratory modeling of environmental problems wherein the transport of mass in a neutral atmospheric surface layer IS solely due to eddies of mechanical origin.

Evaluation of the aquathermolysis catalyst effect on the composition and properties of high-viscosity oil from the Strelovskoe field

The article examines the aquathermolysis process of high viscosity oil from Strelovskoe field developed by RITEK LLC using steam injection. Laboratory modeling of non-catalytic and catalytic aquathermolysis in a high-pressure reactor was performed. Laboratory tests have demonstrated the high efficiency of the iron-based oil-soluble catalyst developed at Kazan Federal University in the destruction reactions of resinous asphaltenes. Samples of the initial oil as well as products of non-catalytic and catalytic aquathermolysis in the presence of iron tallate and the solvent Asphalt-Resin-Paraffin Deposits were studied at temperatures of 200, 250 and 300°C for 24 hours. In addition, the gas composition of the oil aquathermolysis products and the viscosity-temperature characteristics of the oil samples were determined. The studies have shown that catalytic aquathermolysis has a significant effect on the changes in the composition and properties of oil from the Strelovskoe field. It was found that the presence of a catalyst contributes to decarboxylation reactions, increases the degree of desulfurization and decreases the viscosity of oil samples. Keywords: high-viscosity oil; aquathermolysis; catalyst precursor; steam thermal treatment; viscosity.

Mathematical Description and Laboratory Study of Electrophysical Methods of Localization of Geodeformational Changes during the Control of the Railway Roadbed

Currently, the load on railway tracks is increasing due to the increase in freight traffic. Accordingly, more and more serious requirements are being imposed on the reliability of the roadbed, which means that studies of methods for monitoring the integrity of the railway roadbed are relevant. The article provides a mathematical substantiation of the possibility of using seismoelectric and phasemetric methods of geoelectric control of the roadbed of railway tracks in order to identify defects and deformations at an early stage of their occurrence. The methods of laboratory modeling of the natural–technical system “railway track” are considered in order to assess the prospects of using the presented methods. The results of laboratory studies are presented, which have shown their high efficiency in registering a weak useful electrical signal caused by seismoacoustic effects against the background of high-level external industrial and natural interference. In the course of laboratory modeling, it was found that on the amplitude spectra of the output electrical signals of the investigated geological medium in the presence of an elastic harmonic action with a frequency of 70 Hz, the frequency of a harmonic electrical signal with a frequency of 40 Hz is observed. In laboratory modeling, phase images were obtained for the receiving line when simulating the process of sinking the soil base of the railway bed, confirming the presence of a transient process that causes a shift in the initial phase of the signal Δφ = 40° by ~45° (Δφ’ = 85°), which allows detection of the initial stage of failure formation.

On stability boundary of the flow of an acid solution through a chemically active porous medium

It is known that during the flow, if the displacing fluid can chemically react with the components of porous medium and with the release of a gas phase, then such a flow regime can be unstable. During this process, pressure fluctuations can be observed, and the displacing fluid will move in “waves”. In the course of our research, a simple mathematical model was proposed that provides a qualitative explanation of the reasons for the emergence of such a phenomenon; laboratory modeling was carried out, and the criterion of the “waves” formation was found, depending on the concentration of chemically active components. The proposed model can predict the emergence of the wave instabilities in a laboratory experiment, which will allow to carry out a future experiment on a larger scale.

Laboratory modeling of a field-aligned currents system generated by a flow of inner magnetospheric plasma

For the first time in laboratory conditions, an experiment to simulate a system of field-aligned currents arising on planets such as Hot Jupiters in the presence of dense inner-magnetospheric plasma was carried out. The magnitude and transit time of field-aligned currents were measured as a function of the magnetic field using flat electrodes. The geometry of the expansion of plasma streams was pictured by gated camera. Also, in a first approximation, the efficiency of energy transfer from plasma flows to field-aligned currents was calculated. The results obtained create a basis for future laboratory experiments on this topic and improve existing numerical models.