Evolution of the Orszag–Tang vortex system in a compressible medium. I. Initial average subsonic flow
作者:
R. B. Dahlburg,
J. M. Picone,
期刊:
Physics of Fluids B: Plasma Physics
(AIP Available online 1989)
卷期:
Volume 1,
issue 11
页码: 2153-2171
ISSN:0899-8221
年代: 1989
DOI:10.1063/1.859081
出版商: AIP
数据来源: AIP
摘要:
In this paper the results of fully compressible, Fourier collocation, numerical simulations of the Orszag–Tang vortex system are presented. The initial conditions for this system consist of a nonrandom, periodic field in which the magnetic and velocity field contain X points but differ in modal structure along one spatial direction. The velocity field is initially solenoidal, with the total initial pressure field consisting of the superposition of the appropriate incompressible pressure distribution upon a flat pressure field corresponding to the initial, average Mach number of the flow. In these numerical simulations, this initial Mach number is varied from 0.2–0.6. These values correspond to average plasma beta values ranging from 30.0 to 3.3, respectively. It is found that compressible effects develop within one or two Alfve´n transit times, as manifested in the spectra of compressible quantities such as the mass density and the nonsolenoidal flow field. These effects include (1) a retardation of growth of correlation between the magnetic field and the velocity field, (2) the emergence of compressible small‐scale structure such as massive jets, and (3) bifurcation of eddies in the compressible flow field. Differences between the incompressible and compressible results tend to increase with increasing initial average Mach number.
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