Analysis of satellite systems for the periodic survey of the Earth

Satellite systems for the periodic survey of a given range of the Earth’s latitudes have been analyzed. As a rule, the efficiency of the satellite systems is estimated based on the maximum interruption, i.e., the maximum time interval that appears when surveying. However, this performance cannot serve as a full criterion for the quality of the survey, since it does not reflect all survey interruptions with their frequencies. To adequately analyze the operation of the satellite system, it is necessary to use the frequency distribution function of the survey interruptions; its determination is a complex problem and has not yet been solved in the general case. In this paper, we propose a method for calculating the set of all interruptions and frequencies suitable for any multisatellite systems with an arbitrary structure. The method is based on the vector model of the Earth’s survey. To estimate the efficiency of the satellite system operation, a complex criterion has been recommended that takes into account all survey interruptions and their frequencies. Two examples of the application of the developed method have been presented.     

Influence of the disperse phase properties on characteristics of the shock wave passing the direct shock from pure gas in the gas mixture

In this paper, a mathematical model of the nonequilibrium multiphase medium dynamics based on a two-speed two-temperature approximation of interpenetrative continuum mechanics is used to describe the nonstationary processes in a gas suspension. The influence of particle size and their volume content as well as the true density on the process of distributing a shockwave of pure gas into a gas suspension was investigated by means of numerical modeling.     

Coupled CFD/CSD simulation of the helicopter main rotor in high-speed forward flight

The helicopter main rotor in forward flight is considered in this paper. The results for rigid blades and elastic blades are compared by the method of coupled simulation. The influence of the structural damping coefficient on the blade in-flight deformation is also considered.     

Optimization of measurements of the Earth’s radiation belt particle fluxes

The Earth’s radiation belts discovered at the end of the 1950s have great scientific and practical interest. Their main characteristics in magnetically quiet periods are well known. However, the dynamics of the Earth’s radiation belts during magnetic storms and substorms, particularly the dynamics of relativistic electrons of the outer belt, when Earth’s radiation belt particle fluxes undergo significant time variations, is studied insufficiently. At present, principally new experiments have been performed and planned with the intention to better study the dynamics of the Earth’s radiation belts and to operationally control the space-energy distributions of the Earth’s radiation belt particle fluxes. In this paper, for spacecraft designed to measure the fluxes of electrons and protons of the Earth’s radiation belts at altitudes of 0.5–10000 km, the optimal versions for detector orientation and orbital parameters have been considered and selected.     

Radiation environment at the end of active functioning of <Emphasis Type="Italic">Vernov</Emphasis> satellite

Factors of radiation environment in near-Earth space in a period from December 1 to 10, 2014 have been analyzed, which could affect serviceability of the onboard systems of Vernov spacecraft.     

Drop test simulation for a helicopter tail landing gear

The paper describes a mathematical model of drop tests on the landing gear of the Ka-62 helicopter. The model is formulated using the multibody system simulation procedure based on the Lagrange equations of the first kind.     

Algorithm of calculating the light airplane flight performance and rational design airscrew parameters at the preliminary design stage

A technique is proposed of calculating the characteristic flight velocities for an airplane with taking into account the nominal performance of a piston engine. We consider an algorithm of design calculation for the airscrew blade geometry (twist angle, chord and optimal angle of attack along blade). Feasible rational versions of design parameters are discussed.     

Influence of exhaust gas recirculation on technical,economic, and environmental performance of high-uprated diesel aircraft engine

This paper considers the problem of reducing the nitrogen oxide emissions in exhaust gases (EG) of the diesel aircraft engine by exhaust gas recirculation (EGR). The main directions in improving a working process of diesel engines with EGR system were formulated.     

A technique for numerical modeling of liquid film disintegration in the pneumatic injector of aircraft engines

A technique for calculating the two-phase flows in the pneumatic injector of the aircraft engine is developed based on solving the model problem, namely, on verification of the two-phase flow model by means of solving the problem of liquid column disintegration under the effect of an incident airflow. We determine the turbulence models that satisfactorily describe the biphase flow processes.     

A Study of Vibrations of Space Station Structure Elements on the Basis of Video Information

Cosmic Research - The results of the Sreda–MKS space experiment showed that visual data on the vibrations of the ISS structural elements allow one to acquire quantitative characteristics of...