Showing papers by "Arnaud Ferrari published in 1988"
TL;DR: In this paper, the temporal evolution of disturbances in a spherically symmetric polytropic wind from a central object is studied, and the results are derived for solar conditions, but in fact can be applied to outflows in other astrophysical systems.
Abstract: The temporal evolution of disturbances in a spherically symmetric polytropic wind from a central object is studied. Such disturbances may be due to localized momentum addition/subtraction, as, for example, by MHD waves, heating/cooling mechanisms in the outflow, or localized deviations from spherical symmetric expansion. The evolution of an initial perturbed state to a continuous or discontinuous final equilibrium state, as predicted by previous analytic calculations for stationary flows, is followed. It is shown that some of the predicted discontinuous equilibrium states are not physically accessible, while the attainment of the remaining equilibrium states depends on both the temporal and the spatial parameters characterizing the perturbation. The results are derived for solar conditions, but in fact can be applied to outflows in other astrophysical systems. In particular, applications to the solar wind and flows in astrophysical jets are discussed.
8 citations
Journal Article•
TL;DR: In this article, a mesure recentes RX de SS 433 avec le satellite EXOSAT indiquent que les bases des jets consistent en matiere rayonnant thermiquement a des temperatures RX. On montre dans un traitement numerique detaille comment l'instabilite thermique attendue dans le flux en refroidissement evolue
Abstract: Des mesures recentes RX de SS 433 avec le satellite EXOSAT indiquent que les bases des jets consistent en matiere rayonnant thermiquement a des temperatures RX. On montre dans un traitement numerique detaille comment l'instabilite thermique attendue dans le flux en refroidissement evolue
6 citations
TL;DR: In this article, the authors analyzed the finite amplitude stability of a planar shear layer near the marginal stability point in the limit of large wavelengths and small Reynolds numbers and found a subcritical bifurcation and therefore instability to finite amplitude perturbations.
Abstract: We analyze the finite amplitude stability of a planar shear layer near the marginal stability point in the limit of large wavelengths and small Reynolds numbers. We find a subcritical bifurcation and therefore instability to finite amplitude perturbations where linear analysis predicts stability. This result is opposite to that found by previous analyses done in the high Reynolds number regime, where a supercritical bifurcation was found.