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771.
T. Z. Gimadieva 《Russian Aeronautics (Iz VUZ)》2009,52(1):37-40
A mathematical model of motion for a string of liferafts being water dropped is presented under the assumption of a plane system motion. An example of calculations is given. 相似文献
772.
V. S. Moiseev D. S. Gushchina A. N. Kozar G. E. Borzov 《Russian Aeronautics (Iz VUZ)》2009,52(2):221-227
Using formalism of the queueing theory, we propose two-objective models for optimizing the number of unmanned aerial vehicles (UAV) designed for remote monitoring (reconnaissance) of certain regions. A model that takes into account the UAV failure in performing a flight mission is considered. The numerical method and examples of solving problems stated are presented. 相似文献
773.
R. A. Bortnikov 《Russian Aeronautics (Iz VUZ)》2009,52(2):245-249
Alignment charts that make it possible to select a standard size of inert heatexchanger structures with specified output characteristics and a developed scheme of the low-temperature aerosol generator are presented. 相似文献
774.
An effect of the Coriolis forces on the process of gas expansion in the turbine stage is considered. Expressions for efficiency with regard for the radial flow passage are derived. The calculation results and statistical data on the geometric parameters of diagonal stages are presented. 相似文献
775.
N. A. Gureeva 《Russian Aeronautics (Iz VUZ)》2009,52(2):138-144
In the framework of a plane problem of elasticity theory in strength analysis based on the finite element method in the hybrid formulation, we suggest that the approximation of displacements and stresses be used as magnitudes of vector and tensor fields, respectively. The quadrilateral finite element, the displacements and stresses of which are accepted as nodal unknowns is proposed. The mixed Reissner functional is applied to form a finite element deformation matrix. 相似文献
776.
The unsteady aerodynamic loads (pressure increment and generalized forces) acting on a deformable thin airfoil section are determined for its arbitrary motion in the incompressible flow with transverse gusts. In this case, the exact Küssner solution in series is used for harmonic oscillation of an airfoil, in which the Theodorsen function is approximated by a sum of fractional functions with poles. In the time domain, these functions are replaced by the unknown functions that satisfy the one-type ordinary first order differential equations. The equations obtained are combined with the differential equations of the airfoil motion in the generalized coordinates and are used for analyzing the aeroelastic system stability and calculating its dynamic response to gust loads. 相似文献
777.
V. A. Arkhipov 《Russian Aeronautics (Iz VUZ)》2009,52(1):83-87
An approach and algorithms are proposed that make it possible to take into account an effect of magnetic interferences introduced by a mobile object, variation of its inclination angles and, hence, to improve precision of the magneto-inertial horizon-compass operation. 相似文献
778.
Based on the archive OMNI data for the period 1976–2000 an analysis has been made of 798 geomagnetic storms with D
st
< −50 nT and their interplanetary sources-large-scale types of the solar wind: CIR (145 magnetic storms), Sheath (96), magnetic
clouds MC (62), and Ejecta (161). The remaining 334 magnetic storms have no well-defined sources. For the analysis, we applied
the double method of superposed epoch analysis in which the instants of the magnetic storm beginning and minimum of D
st
index are taken as reference times. The well-known fact that, independent of the interplanetary source type, the magnetic
storm begins in 1–2 h after a southward turn of the IMF (B
z
< 0) and both the end of the main phase of a storm and the beginning of its recovery phase are observed in 1–2 h after disappearance
of the southward component of the IMF is confirmed. Also confirmed is the result obtained previously that the most efficient
generation of magnetic storms is observed for Sheath before MC. On the average parameters B
z
and E
y
slightly vary between the beginning and end of the main phase of storms (minimum of D
st
and D
st
* indices), while D
st
and D
st
* indices decrease monotonically proportionally to integral of B
z
and E
y
over time. Such a behavior of the indices indicates that the used double method of superposed epoch analysis can be successfully
applied in order to study dynamics of the parameters on the main phase of magnetic storms having different duration. 相似文献
779.
V. A. Gladyshev A. Yu. Shchekotov N. V. Yagova J. -J. Berthelier M. Parrot O. S. Akent’eva L. N. Baranskii E. N. Fedorov T. M. Mulyarchik O. A. Molchanov 《Cosmic Research》2012,50(2):103-115
Variations in concentration of ions H+, He+, and O+ are studied at a height of about 700 km using the data of continuous observations onboard the DEMETER satellite at the decline and in the minimum of solar activity from 2004 to 2008. Latitudinal distributions, seasonal behavior,
and irregular variations in ion concentrations and their dependence on solar and geomagnetic activity are considered. Within
this altitude range, for the first time an analysis is performed of the dataset of many-year continuous observations in both
hemispheres from the equatorial to subauroral latitudes. This made it possible to describe the seasonal and irregular variations
of the concentrations of main ion species with better time and spatial resolution than in the available empirical models.
The dependence of concentrations of three types of ions on solar and geomagnetic activity is studied at time scales from several
days to several years, and it is shown that the anti-phase change in concentrations of O+ and light ions known from publications is partly a result of mutual dependence of solar and geomagnetic activity and is observed
only at time scales beginning from several months. At time scales from several days to several weeks, variations in the concentration
of O+ and light ions are governed mainly by solar and geomagnetic activity, respectively. 相似文献
780.
O. B. Barysheva 《Russian Aeronautics (Iz VUZ)》2007,50(4):374-379
The behavior of generalized diffusion coefficients and diffusion flows of individual substances in the multicomponent gas mixture is investigated. The combustion products of liquid rocket propellants being used are considered. 相似文献