Том 63, № 9 (2018)

The spatial problem of the aerophysics of a superorbital entry of the Apollo-4 command module into the dense layers of the Earth’s atmosphere at an angle of attack of 25°, an entry velocity V_∞ = 10.7 km s^–1, and altitudes of 91.5 and 76.2 km has been solved. The distributions of the spectral and integral radiative heat flux densities along the entire streamlined surface have been derived. A significant role of the electronic bands of diatomic molecules in the radiative heating of the surface has been shown.

The physical mechanism of reverse magnetization jumps, which are induced by the minimization of the total energy of a growing magnetic phase in the process of magnetization of a ferromagnetic, is revealed. The ways toward enhancing the magnetic induction and suppressing the magnetostriction and magnetic losses in Fe–3% Si alloys through adjustment of the parameters of magnetization jumps are outlined. The effective refinement of the structure of magnetic materials leads to a considerable improvement in the magnetic characteristics.

The motion of a liquid column in a vertical pipe caused by a moving piston touching its lower boundary is considered. The law of motion of the piston is set on the basis of experimental data. The acceleration of the piston exceeds the acceleration due to gravity. Liquid separation from the piston and the change in the cavitation-pocket volume are admitted. The simplest model of the phenomenon is proposed. A qualitative analytical solution of the one-dimensional problem and a comparison with experimental data are provided.

A laminar compressible boundary layer on a permeable plate under blowing at small and large Prandtl numbers is investigated numerically. For Prandtl numbers Pr < 1 and the temperature of the gas blown lower than the temperature of the adiabatic impenetrable wall, the calculations carried out confirm the existence of a region of the permeable wall where the temperature is lower than the temperature of the blown gas. For Prandtl numbers Pr > 1 at a blown-gas temperature higher than that of the adiabatic impenetrable wall, the temperature of the permeable wall is higher than that of the blown gas.

This work contains a generalization of Kapitsa’s classical problem. The stability of the vertical position of a flexible rod with a lower support point under gravity and vibrations is considered. It has been shown that an unstable position can become stable in the presence of vertical harmonic vibrations of the base. Both rigid and hinge fixing of the lower rod end are considered. In the linear approximation, the problem is reduced to transverse oscillations of the rod under the action of periodic axial compression. The solution is obtained in two formulations—taking into account the propagation of longitudinal waves in the rod and without regard for it. It turns out that longitudinal waves significantly reduce the base vibration level necessary for the stability.

An approach is proposed on the basis of more precise formulations of the forecasting problem and developed within the framework of variation principles for the solution of inverse problems, into which precise estimation of forecast solutions is incorporated for the first time, thus providing the possibility to obtain new scientifically substantiated results and achieve a required precision of forecasting. An original model is constructed to forecast the residual life and longevity of composites and describe the processes occurring in polymer composite materials and structures under the simultaneous influence of several destabilizing physical factors at the physical level. The application of a newly formulated principle of multiplicity for forecasting models and the first constructed multiparametric models of optimal complexity within the refined variation formulation of inverse forecasting problems of the residual life has appreciably improved the precision of solution for inverse forecasting problems and enhanced the time interval within which the time dependence of the residual life and longevity of composites can be predicted at a specified maximum permissible precision of forecasting. The proposed approach can be used to solve a broad range of problems of forecasting the residual life, longevity, and strength of composites.