V.?A.?Afanas’ev  G.?L.?Degtyarev  A.?S.?Meshchanov  "mailto:mas@list.ru  " title=  "mas@list.ru  " itemprop=  "email  " data-track=  "click  " data-track-action=  "Email author  " data-track-label=  "  ">Email author 《Russian Aeronautics (Iz VUZ)》2018,61(1):23-31

Real values of parameters for a space vehicle and its steering devices are specified by using the motion parameters measured in flight based on solving the differential equations of motion.  相似文献   

    

A. V. Ivanov  A. V. Moskvichev 《Russian Aeronautics (Iz VUZ)》2017,60(2):223-228

The paper discusses the applicability of cold gaseous nitrogen as a model working fluid in testing the hydrogen pump seals for power plants by three-dimensional modeling.  相似文献   

    

Yu. A. Gravchenko  B. K. Grankin  V. V. Kozlov  S. V. Chirva 《Russian Aeronautics (Iz VUZ)》2017,60(3):327-334

The paper adduces the relators for algebraic operations on graphs using the numeric codes of the graphs. The special algebra of codes has been devised with consideration of the principles of graph transformation. This paper demonstrates the relevance of numeric coding of graphs for solving the problems of enumeration, systematization, and compact representation of the information about the structural and functional characteristics of the systems of flow distribution and conversion of rocket and space technology and for conducting the modeling transformations of given systems in the course of the structural and functional studies as well.  相似文献   

    

David G. Sibeck  R. Allen  H. Aryan  D. Bodewits  P. Brandt  G. Branduardi-Raymont  G. Brown  J. A. Carter  Y. M. Collado-Vega  M. R. Collier  H. K. Connor  T. E. Cravens  Y. Ezoe  M.-C. Fok  M. Galeazzi  O. Gutynska  M. Holmström  S.-Y. Hsieh  K. Ishikawa  D. Koutroumpa  K. D. Kuntz  M. Leutenegger  Y. Miyoshi  F. S. Porter  M. E. Purucker  A. M. Read  J. Raeder  I. P. Robertson  A. A. Samsonov  S. Sembay  S. L. Snowden  N. E. Thomas  R. von Steiger  B. M. Walsh  S. Wing 《Space Science Reviews》2018,214(4):79

Both heliophysics and planetary physics seek to understand the complex nature of the solar wind’s interaction with solar system obstacles like Earth’s magnetosphere, the ionospheres of Venus and Mars, and comets. Studies with this objective are frequently conducted with the help of single or multipoint in situ electromagnetic field and particle observations, guided by the predictions of both local and global numerical simulations, and placed in context by observations from far and extreme ultraviolet (FUV, EUV), hard X-ray, and energetic neutral atom imagers (ENA). Each proposed interaction mechanism (e.g., steady or transient magnetic reconnection, local or global magnetic reconnection, ion pick-up, or the Kelvin-Helmholtz instability) generates diagnostic plasma density structures. The significance of each mechanism to the overall interaction (as measured in terms of atmospheric/ionospheric loss at comets, Venus, and Mars or global magnetospheric/ionospheric convection at Earth) remains to be determined but can be evaluated on the basis of how often the density signatures that it generates are observed as a function of solar wind conditions. This paper reviews efforts to image the diagnostic plasma density structures in the soft (low energy, 0.1–2.0 keV) X-rays produced when high charge state solar wind ions exchange electrons with the exospheric neutrals surrounding solar system obstacles.The introduction notes that theory, local, and global simulations predict the characteristics of plasma boundaries such the bow shock and magnetopause (including location, density gradient, and motion) and regions such as the magnetosheath (including density and width) as a function of location, solar wind conditions, and the particular mechanism operating. In situ measurements confirm the existence of time- and spatial-dependent plasma density structures like the bow shock, magnetosheath, and magnetopause/ionopause at Venus, Mars, comets, and the Earth. However, in situ measurements rarely suffice to determine the global extent of these density structures or their global variation as a function of solar wind conditions, except in the form of empirical studies based on observations from many different times and solar wind conditions. Remote sensing observations provide global information about auroral ovals (FUV and hard X-ray), the terrestrial plasmasphere (EUV), and the terrestrial ring current (ENA). ENA instruments with low energy thresholds ((sim1~mbox{keV})) have recently been used to obtain important information concerning the magnetosheaths of Venus, Mars, and the Earth. Recent technological developments make these magnetosheaths valuable potential targets for high-cadence wide-field-of-view soft X-ray imagers.Section 2 describes proposed dayside interaction mechanisms, including reconnection, the Kelvin-Helmholtz instability, and other processes in greater detail with an emphasis on the plasma density structures that they generate. It focuses upon the questions that remain as yet unanswered, such as the significance of each proposed interaction mode, which can be determined from its occurrence pattern as a function of location and solar wind conditions. Section 3 outlines the physics underlying the charge exchange generation of soft X-rays. Section 4 lists the background sources (helium focusing cone, planetary, and cosmic) of soft X-rays from which the charge exchange emissions generated by solar wind exchange must be distinguished. With the help of simulations employing state-of-the-art magnetohydrodynamic models for the solar wind-magnetosphere interaction, models for Earth’s exosphere, and knowledge concerning these background emissions, Sect. 5 demonstrates that boundaries and regions such as the bow shock, magnetosheath, magnetopause, and cusps can readily be identified in images of charge exchange emissions. Section 6 reviews observations by (generally narrow) field of view (FOV) astrophysical telescopes that confirm the presence of these emissions at the intensities predicted by the simulations. Section 7 describes the design of a notional wide FOV “lobster-eye” telescope capable of imaging the global interactions and shows how it might be used to extract information concerning the global interaction of the solar wind with solar system obstacles. The conclusion outlines prospects for missions employing such wide FOV imagers.  相似文献   

    

V. Biffi  F. Mernier  P. Medvedev 《Space Science Reviews》2018,214(8):123

The distribution of chemical elements in the hot intracluster medium (ICM) retains valuable information about the enrichment and star formation histories of galaxy clusters, and on the feedback and dynamical processes driving the evolution of the cosmic baryons. In the present study we review the progresses made so far in the modelling of the ICM chemical enrichment in a cosmological context, focusing in particular on cosmological hydrodynamical simulations. We will review the key aspects of embedding chemical evolution models into hydrodynamical simulations, with special attention to the crucial assumptions on the initial stellar mass function, stellar lifetimes and metal yields, and to the numerical limitations of the modelling. At a second stage, we will overview the main simulation results obtained in the last decades and compare them to X-ray observations of the ICM enrichment patterns. In particular, we will discuss how state-of-the-art simulations are able to reproduce the observed radial distribution of metals in the ICM, from the core to the outskirts, the chemical diversity depending on cluster thermo-dynamical properties, the evolution of ICM metallicity and its dependency on the system mass from group to cluster scales. Finally, we will discuss the limitations still present in modern cosmological, chemical, hydrodynamical simulations and the perspectives for improving the theoretical modelling of the ICM enrichment in galaxy clusters in the future.  相似文献   

    

E. J. Speyerer  R. V. Wagner  M. S. Robinson  A. Licht  P. C. Thomas  K. Becker  J. Anderson  S. M. Brylow  D. C. Humm  M. Tschimmel 《Space Science Reviews》2016,200(1-4):357-392

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Nicholas Achilleos  Nicolas André  Xochitl Blanco-Cano  Pontus C. Brandt  Peter A. Delamere  Robert Winglee 《Space Science Reviews》2015,187(1-4):229-299

The rapid rotation of the gas giant planets, Jupiter and Saturn, leads to the formation of magnetodisc regions in their magnetospheric environments. In these regions, relatively cold plasma is confined towards the equatorial regions, and the magnetic field generated by the azimuthal (ring) current adds to the planetary dipole, forming radially distended field lines near the equatorial plane. The ensuing force balance in the equatorial magnetodisc is strongly influenced by centrifugal stress and by the thermal pressure of hot ion populations, whose thermal energy is large compared to the magnitude of their centrifugal potential energy. The sources of plasma for the Jovian and Kronian magnetospheres are the respective satellites Io (a volcanic moon) and Enceladus (an icy moon). The plasma produced by these sources is globally transported outwards through the respective magnetosphere, and ultimately lost from the system. One of the most studied mechanisms for this transport is flux tube interchange, a plasma instability which displaces mass but does not displace magnetic flux—an important observational constraint for any transport process. Pressure anisotropy is likely to play a role in the loss of plasma from these magnetospheres. This is especially the case for the Jovian system, which can harbour strong parallel pressures at the equatorial segments of rotating, expanding flux tubes, leading to these regions becoming unstable, blowing open and releasing their plasma. Plasma mass loss is also associated with magnetic reconnection events in the magnetotail regions. In this overview, we summarise some important observational and theoretical concepts associated with the production and transport of plasma in giant planet magnetodiscs. We begin by considering aspects of force balance in these systems, and their coupling with the ionospheres of their parent planets. We then describe the role of the interaction between neutral and ionized species, and how it determines the rate at which plasma mass and momentum are added to the magnetodisc. Following this, we describe the observational properties of plasma injections, and the consequent implications for the nature of global plasma transport and magnetodisc stability. The theory of the flux tube interchange instability is reviewed, and the influences of gravity and magnetic curvature on the instability are described. The interaction between simulated interchange plasma structures and Saturn’s moon Titan is discussed, and its relationship to observed periodic phenomena at Saturn is described. Finally, the observation, generation and evolution of plasma waves associated with mass loading in the magnetodisc regions is reviewed.  相似文献   

    

V. S. Brusov  S. A. Piyavskii 《Russian Aeronautics (Iz VUZ)》2016,59(4):447-451

In this paper, we consider an example of estimating and comparing the efficiency of different concepts for a high-altitude unmanned aerial vehicle (UAV) under diversity of efficiency criteria.  相似文献   

    

A.?E.?Remizov  V.?V.?Vyatkov  V.?A.?Lebedev  "mailto:lebedevvlad@mail.ru  " title=  "lebedevvlad@mail.ru  " itemprop=  "email  " data-track=  "click  " data-track-action=  "Email author  " data-track-label=  "  ">Email author 《Russian Aeronautics (Iz VUZ)》2016,59(4):559-564

Methods to control flow have been considered in order to reduce end losses in blade rows of GTE gas turbines by means of measures taken at the design stage.  相似文献   

    

R. R. Faizullin  V. V. Kadushkin  M. S. Vorob’ev 《Russian Aeronautics (Iz VUZ)》2015,58(3):345-350

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