Kelvin-Helmholtz instability in three dimensional radiative jets
2000; EDP Sciences; Volume: 360; Linguagem: Inglês
ISSN
1432-0746
AutoresM. Micono, G. Bodo, S. Massaglia, P. Rossi, A. Ferrari, R. Rosner,
Tópico(s)Fluid Dynamics and Turbulent Flows
ResumoThe analysis of the stability properties of astrophys- ical jets against Kelvin-Helmholtz (or shear-layer) instabilities plays a basic role in the understanding of the origin and physical characteristics of these objects. Numerical simulations by Bodo et al. (1998) have shown that the three-dimensional non-linear evolution of KH instabilities in supersonic jets is substantially faster than in the two-dimensional case, leading to a cascade of modes towards smaller scales and a very effective mixing and momentum transfer to the ambient medium. On the other hand, Rossi et al. (1997) and Micono et al. (1998) found, in two di- mensions, that radiative losses tend to reduce and delay mixing effects and momentum transfer to the ambient medium. In this paper, as a logical next step, we investigate the effects of radia- tive losses on the stability of 3D supersonic jets, assuming that the internal jet density is initially lower, equal and higher than the ambient medium, respectively. We find that light and equal- density radiative jets evolve in a qualitatively similar fashion with respect to the corresponding adiabatic ones. Conversely, we note substantial differences in the evolution of heavy jets: they remain more collimated and do not spread out, while the momentum gained by the ambient medium stays within 5 jet radii.
Referência(s)