scholarly journals Numerical Analysis of High Altitude Aerodynamics of Reentry Vehicles

Author(s):  
Pavel Vashchenkov ◽  
Aleksandr Kashkovsky ◽  
Mikhail Ivanov ◽  
Andrey Krylov
Energies ◽  
2020 ◽  
Vol 13 (16) ◽  
pp. 4155
Author(s):  
Feng Wu ◽  
Limin Gao ◽  
Lu Yang ◽  
Aqiang Lin ◽  
Hai Zhang

A numerical analysis is performed to explore the high altitude and high Mach flight on the effect of wall boundary layer loss in the compressor. The accuracy for solution results by the application of the similarity criterion and parameter definition of the air inlet is compared with the existing experimental test result. The results indicate that the radial adverse pressure gradient in the rotor domain gradually increases along the span direction and decreases as flight Mach number increases; meanwhile, the circumferential adverse pressure gradient on the pressure side of the rotor blade is correspondingly larger and less than that on the suction side. In particular, the entropy increase along the streamwise shows a decreasing trend and an increasing trend inside the hub and shroud wall boundary layers, respectively. At 2.1 Ma, the entropy increase in the rotor domains enhances by 24.36–27.80% inside the shroud boundary layer, relative to the hub boundary layer; however, it decreases by 0.97–8.54% in the stator domain. With the increase in flight Mach number from 2.1 to 3.4, the average entropy increase reductions in the rotor domain decrease by 18.99–24.97% within the hub boundary layer and 5.71–8.1% within the shroud boundary layer. In the stator domain, it drops by 18.45–9.03% inside the hub boundary layer and 6.88–8.67% inside the shroud boundary layer. It was therefore found that, as Mach number increases from 2.1 to 3.4, the entropy increase reduction is larger inside the hub boundary layer than inside the shroud boundary layer.


2019 ◽  
Vol 487 (6) ◽  
pp. 684-690
Author(s):  
O. A. Razorenova ◽  
P. A. Shabanov

An updated climatology of upper level frontal zones (UFZ) of the Northern Hemisphere is presented, based on a numerical analysis of geopotential gradients and the allocation of maximum gradient zones. Differences in the position of the UFZ during the development of meridional and zonal processes are revealed. Based on the analysis of years with the predominance of various forms of circulation, it is shown that the position of high-altitude frontal zones is an objective diagnostic tool for studying modern climate variability.


2019 ◽  
Vol 23 (1) ◽  
pp. 52-60 ◽  
Author(s):  
Donghae Shin ◽  
Isang Yu ◽  
Minku Shin ◽  
Jeonghwa Oh ◽  
Youngsung Ko ◽  
...  

1994 ◽  
Vol 144 ◽  
pp. 365-367
Author(s):  
E. V. Kononovich ◽  
O. B. Smirnova ◽  
P. Heinzel ◽  
P. Kotrč

AbstractThe Hα filtergrams obtained at Tjan-Shan High Altitude Observatory near Alma-Ata (Moscow University Station) were measured in order to specify the bright rims contrast at different points along the line profile (0.0; ± 0.25; ± 0.5; ± 0.75 and ± 1.0 Å). The mean contrast value in the line center is about 25 percent. The bright rims interpretation as the bases of magnetic structures supporting the filaments is suggested.


Author(s):  
D. M. Davies ◽  
R. Kemner ◽  
E. F. Fullam

All serious electron microscopists at one time or another have been concerned with the cleanliness and freedom from artifacts of thin film specimen support substrates. This is particularly important where there are relatively few particles of a sample to be found for study, as in the case of micrometeorite collections. For the deposition of such celestial garbage through the use of balloons, rockets, and aircraft, the thin film substrates must have not only all the attributes necessary for use in the electron microscope, but also be able to withstand rather wide temperature variations at high altitude, vibration and shock inherent in the collection vehicle's operation and occasionally an unscheduled violent landing.Nitrocellulose has been selected as a film forming material that meets these requirements yet lends itself to a relatively simple clean-up procedure to remove particulate contaminants. A 1% nitrocellulose solution is prepared by dissolving “Parlodion” in redistilled amyl acetate from which all moisture has been removed.


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