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941.
A comprehensive numerical study of transient interchamber processes occurring when reaching the SPRE operational conditions
is carried out. A conjugate problem under consideration includes nonstationary operation of an igniter heating, ignition and
subsequent nonstationary and turbulent burning of a solid-propellant charge; nonstationary three-phase homo-heterogeneous
flow of combustion products in the combustion chamber, nozzle and downstream of the nozzle block of a rocket engine; motion
of a nozzle block cover. The calculation results are presented. 相似文献
942.
A numerical and analytical method for constructing a shape of the axisymmetric body streamlined with jet blowout by the specified
velocity distribution along its meridian section is proposed. The foundation of the method is the iteration process based
on the solutions of an inverse problem in the plane case and a primal problem for the axisymmetric body. A program realizing
the iteration process is set up and examples of numerical calculations are given. 相似文献
943.
A recursive method for calculating decoupling zeroes in the linear multiconnected dynamic system based on the application
of matrix canonization techniques is proposed. Its essence is that the problem dimension is successively decreased and reduced
to finding eigenvalues of some matrix. The results obtained can be used to check controllability and observability as well
as to calculate uncontrollable and unobservable modes of the dynamic system. 相似文献
944.
V. R. Rubinskii S. P. Khrisanfov V. Yu. Klimov A. V. Kretinin 《Russian Aeronautics (Iz VUZ)》2010,53(1):81-86
The numerical results are presented for the case of coaxial-jet supply at the different ratio of mass component velocities
at the combustion chamber inlet with the constant and variable relationship of oxygen-methane components. The experimental
investigations of coaxial-jet mixing elements as part of the model setup chamber operating on corrosive producer gas and gaseous
methane were carried out. A qualitative pattern of the $
\overline {\rho u}
$
\overline {\rho u}
parameter influence on the chamber economic feasibility was obtained: as $
\overline {\rho u}
$
\overline {\rho u}
decreases, the combustion efficiency coefficient grows. 相似文献
945.
Ricardo Hueso J. Legarreta J.F. Rojas J. Peralta S. Pérez-Hoyos T. del Río-Gaztelurrutia A. Sánchez-Lavega 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2010
The observation, characterization, and understanding of planetary atmospheres are key components of Solar System exploration. Their study requires, among other observations, the use of image data acquired from spacecrafts. The basic tasks that are generally used to work with planetary image data are: image navigation, projection, image processing, limb-darkening correction, composition of multiwavelength images and mosaicing. We illustrate the mathematical techniques required for the study of planetary images obtained from spacecrafts using as an example our own software package (PLIA). We present examples of analysis of Galileo SSI, Cassini ISS and Venus Express VIRTIS observations covering a large range of image peculiarities. The paper is organized as a guide for anyone willing to replicate one or several of the capabilities incorporated in the PLIA software. An open source version of PLIA for astronomical image processing is available. 相似文献
946.
Alankrita Isha Mrigakshi Daniel Matthiä Thomas Berger Günther Reitz Robert F. Wimmer-Schweingruber 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2013
The evidently low solar activity observed between solar cycles 23 and 24 during the years 2008–2010 led to a substantial increase in the Galactic Cosmic Ray (GCR) intensity in comparison with preceding solar minima. As the GCRs consist of highly-ionizing charged particles having the potential to cause biological damage, they are a subject of concern for manned missions to space. With the enhanced particle fluxes observed between 2008 and 2010, it is reasonable to assume that the radiation exposure from GCR must have also increased to unusually high levels. In this paper, the GCR exposure outside and inside the Earth’s magnetosphere is numerically calculated for time periods starting from 1970 to the end of 2011 in order to investigate the increase in dose levels during the years 2008–2010 in comparison with the last three solar minima. The dose rates were calculated in a water sphere, used as a surrogate for the human body, either unshielded or surrounded by aluminium shielding of 0.3, 10 or 40 g/cm2. 相似文献
947.
The trend toward digital processing of radar and sonar signals has ledto the use of ?baseband? or bipolar video signals. The processingof both the in-phase (I) and quadrature (Q) channels generally allows an exact representation of the signals, and no loss of sensitivity need occur. However, for reasons of economy or weight only one channel is often implemented. This correspondence shows that the sensitivity loss for this case often deviates considerably from the 3-dB rule of thumb. 相似文献
948.
A mathematical algorithm using the method of invariant imbedding is developed which generates a best £2 estimate of range and range rate from pulse Doppler data. 相似文献
949.
Crewmembers play an important role in ensuring the efficiency of "crew-spacecraft" system. However, despite of the fact that crewmembers are well trained and highly motivated persons, extreme flight factors may influence negatively on their reliability, and lead to human error occurrence. Therefore, working out methods of human error prevention is very significant to increase crewmember's performance reliability. Human error can occur in the operation of systems for a number of reasons. Within the framework of the present investigation, with use the data collected during "Mir" station missions, the significant (p<0.05) positive correlation of crewmembers errors (CE) frequency with their psychophysiological state (PPS), and work and rest schedule (WRS) intensity has been revealed. Differently, the higher WRS intensity, the crewmember's PPS is worse, and CE frequency is higher. This finding has been based on substantiations of the approach to human reliability management. Its essence will consist of the following: reducing WRS intensity, we thus can improve a crewmember's PPS and, accordingly, reduce CE frequency. This approach is discussed in the paper. 相似文献
950.