scholarly journals PROPERTIES OF ACCRETION SHOCK WAVES IN VISCOUS FLOWS WITH COOLING EFFECTS

Author(s):  
SANTABRATA DAS ◽  
SANDIP K. CHAKRABARTI
2004 ◽  
Vol 13 (09) ◽  
pp. 1955-1972 ◽  
Author(s):  
SANTABRATA DAS ◽  
SANDIP K. CHAKRABARTI

Low angular momentum accretion flows can have standing and oscillating shock waves. We study the region of the parameter space in which multiple sonic points occur in viscous flows in presence of various cooling effects such as bremsstrahlung and Comptonization. We also quantify the parameter space in which shocks are steady or oscillating. We find that cooling induces effects opposite to heating by viscosity even in modifying the topology of the solutions, though one can never be exactly balanced by the other due to their dissimilar dependence on dynamic and thermodynamic parameters. We show that beyond a critical value of cooling, the flow ceases to contain a shock wave.


2021 ◽  
Vol 63 (1) ◽  
Author(s):  
Léo Kovacs ◽  
Pierre-Yves Passaggia ◽  
Nicolas Mazellier ◽  
Viviana Lago

1983 ◽  
Vol 50 (2) ◽  
pp. 265-269
Author(s):  
D. Nixon

The perturbation theory for transonic flow is further developed for solutions of the Navier-Stokes equations in two dimensions or for experimental results. The strained coordinate technique is used to treat changes in location of any shock waves or large gradients.


2008 ◽  
Author(s):  
Santabrata Das ◽  
Sandip K. Chakrabarti ◽  
Sandip K. Chakrabarti ◽  
Archan S. Majumdar

Author(s):  
M.A. Mogilevsky ◽  
L.S. Bushnev

Single crystals of Al were loaded by 15 to 40 GPa shock waves at 77 K with a pulse duration of 1.0 to 0.5 μs and a residual deformation of ∼1%. The analysis of deformation structure peculiarities allows the deformation history to be re-established.After a 20 to 40 GPa loading the dislocation density in the recovered samples was about 1010 cm-2. By measuring the thickness of the 40 GPa shock front in Al, a plastic deformation velocity of 1.07 x 108 s-1 is obtained, from where the moving dislocation density at the front is 7 x 1010 cm-2. A very small part of dislocations moves during the whole time of compression, i.e. a total dislocation density at the front must be in excess of this value by one or two orders. Consequently, due to extremely high stresses, at the front there exists a very unstable structure which is rearranged later with a noticeable decrease in dislocation density.


2006 ◽  
Vol 134 ◽  
pp. 237-241
Author(s):  
J. L. Dequiedt
Keyword(s):  

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