1996/07/17 by A. D. Rogava, Rogava, A. D., V. I. Berezhiani +4
Engineering · Physics and Astronomy · #Aerodynamics and Acoustics in Jet Flows #Astrophysics (astro-ph) #FOS: Physical sciences #Fluid Dynamics and Turbulent Flows #Solar and Space Plasma Dynamics #astro-ph
paper · pdf · doi:10.48550/arxiv.astro-ph/9607085
17 pages, LATEX, no figures
arxiv created 1996/07/17 · openalex publication_date 1996/07/17 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Acoustic perturbations in a parallel relativistic flow of an inviscid fluid are considered. The general expression for the frequency of the sound waves in a uniformly (with zero shear) moving medium is derived. It is shown that relativity evokes a difference in the frequencies of the sound-type perturbations propagating along and against the current. Besides, it is shown that the perturbations are not purely irrotational as they are in nonrelativistic case. For a non-uniformly (with nonzero shear) moving fluid a general set of equations, describing the evolution of the acoustic perturbations in relativistic sheared flows, is obtained and analysed when the temperature is nonrelativistic. It is shown that, like the nonrelativistic case, in the new system: (a) the excitation of vortical, transiently growing perturbations, and (b) the excitation of sound-type perturbations, extracting the kinetic energy of the background flow, are possible. It is demonstrated that the relativistic character of the motion significantly intensifies the efficiency of both these processes. Finally, the possible relevance of this study to processes in astrophysical shear flows is pointed out.