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Two methods are developed for determining the equivalent aerodynamic damping of reentry vehicle models. In the first method, the equivalent aerodynamic damping is determined on the basis of the experimental envelopes of the transitional process for the angle of attack changing with time; in the second method, all experimental points of the transitional process are involved. Both methods are found to produce similar results. The adequacy of the methods is verified by an example of a reentry vehicle model, which demonstrates that the predicted transitional processes for the angle of attack changing with time are in good agreement with the experimental data.

The effectiveness of use of an ejector pump for controlling the flow around a wing under take-off and landing conditions of flight is investigated. The proposed device permits organization of simultaneous suction of boundary layer through a slot on the upper surface of the wing and gas blowing in the vicinity of the trailing edge of wing through a flat slot-type diffuser; the latter makes it possible to effectively implement the principle of wing-flow control using gas suction and jet blowing. The design of the ejector pump makes it possible to obtain values of suction and blowing velocities of order 50-100 m/s. The paper proposes a mathematical model of the flow around the wing airfoil taking into account the operation of the ejector pump, and presents results of a computational study of aerodynamic characteristics of one- and three-element wing airfoil under landing conditions. It is shown that the simultaneous use of suction and blowing improves the flight characteristics of the mechanized airfoil more effectively in comparison with the separate use of these means.

The results of numerical investigation of the interaction of a supersonic free stream with the Mach number of 3.85 with a transverse gas jet blown from the surface of an axisymmetric model located at zero angle of attack with respect to the flow are presented. The numerical modeling was conducted using the averaged Navier-Stokes equations employing the k-w SST turbulence model. The investigation of the influence of the gas jet blowing on pressure redistribution over the axisymmetric model surface and on the formation of an additional transverse force and moment has also been conducted. The shift of the blowing orifice along the model length leads to a significant variation of arising forces and moments. A fundamental difference in the distribution of pressures over the surface at the jet blowing from the axisymmetric body and from a flat plate is shown.

The peculiarities of the change of the regimes “diffusion-gravitational concentration convection” have been studied numerically. It is shown that at a certain mixture composition and pressure, substantially nonlinear distributions of the concentrations of components arise at the expense of the difference in the diffusion coefficients of components, which lead to the corresponding distribution of the gaseous mixture density. This is a reason for the formation of structured formations and the rise of convective instability in the mixtures under study. The time of the rise of convective flows and of the mean velocity of the components transfer has been estimated. Obtained results are compared with experimental data.

Experiments on the effect of two-layer compliant coatings on the surface friction of a flat plate at flow velocities of up to 16 m/s carried out in a water tunnel are described. To document the properties of the coatings, the dynamic viscoelastic properties of used rubbers were measured in the frequency range approximately corresponding to the frequency range of wall pressure oscillations at current flow velocities. The data on characteristics of the viscoelastic properties of coatings and experimental data on interaction of coatings with the flow form a database required to test various theories and semi-empirical models for predicting the effectiveness of such interaction.

Initiating detonation in a reactive hydrogen-oxygen mixture by a spherical projectile of small diameter, flying with velocity exceeding the Chapman-Jouguet one, has been studied numerically. The mathematical model is based on the given kinetic scheme for the description of chemical reactions. At verification of the computational algorithm, the flow regimes and the detonation cell size were compared for numerical and experimental data. The agreement between the calculated and the experimental flow patterns and the quantitative correspondence of the modes of existence of inclined detonation waves have been obtained.

The paper presents a method for study of thermal emission characteristics from heterogeneous combustion products in a plume of a model solid-fuel rocket engine. Simulation experiments found the influence of speed and temperature types of non-equilibrium on spectral and integral densities of radiation energy flux and emissivity factors. The values of non-equilibrium were determined at different critical nozzle cross sections and at different average sizes of particle. It was found that the speed non-equilibrium has a minor influence within the gas emission bands; meanwhile it is stronger for transparency bands of gas phase. The non-equilibrium in temperature is the main factor in calculating the emission characteristics of the flow, while the speed delay of particles relative the gas flow is manifested stronger at this background.

The experimental procedure is presented for range test of critical flame spread in the conditions of uniform distribution of particles in dust cloud under varied temperature of the ignition initiation source. Fire and explosion hazard of coal dust is estimated by the method of successive approximations. The feasibility of studying the cold flame effect in inflammation of coal dust suspension in air and its transition to the hot mode burning when dust concentration grows is demonstrated, which is of importance for the theory of safety technology.

The mathematical model of hydro vortex inertial kinematic coagulation is proposed; the model largely improves energy efficiency of coal dust blast isolation. The graphical model of interaction between liquid drop and explosive aerosol particle at the contact zone at the moment of collision in the liquid-solid system is refined using the theory of added vortexes. The hypothesis on weakening of the wedge effect of a gas medium in the zone of contact between the explosive aerosol particle owing to an added vortex caused by the drop and particle rotation, is put forward and proved. The equations are obtained for calculating energy required for total absorption of explosive aerosol particles, minimum diameter of the particles and wetting angle in hydro vortex inertial coagulation.

The authors present a WI-Fi ad hoc wireless senor communication network for information transmission between data loggers and mobile station (smartphones). The wireless data transmission follows from an underground station to a worker’s smartphone and, then, after the worker has left the mine, to a data logger on the surface. The serviceability of this system was tested by measurement of communication quality indexes in various environments. The tests show that wireless communication between a stationary point and a mobile devise is possible at transfer speeds up to 2 MB/s with a PER below 25% either at a maximum distance of 110 m in a straight path or at a distance of 20 m in case of a corner or turn of the path. The proposed system allows the transmission of 39.6-79.2 MB of monitoring data to a worker moving at 20 km/h.