Data/hora: 01/06/2024 09:20:22

Provedor de dados: 	5	
País: 	France	
Título: 	An hydrodynamic shear instability in stratified disks	
Autores: 	Dubrulle, B; Marie, Louis; Normand, C; Richard, D; Hersant, F; Zahn, Jp.	
Data: 	2005-01	
Ano: 	2005	
Palavras-chave: 	Accretion; Accretion disks hydrodynamic instabilities turbulence.	
Resumo: 	We discuss the possibility that astrophysical accretion disks are dynamically unstable to non-axisymmetric disturbances with characteristic scales much smaller than the vertical scale height. The instability is studied using three methods: one based on the energy integral, which allows the determination of a sufficient condition of stability, one using a WKB approach, which allows the determination of the necessary and sufficient condition for instability and a last one by numerical solution. This linear instability occurs in any inviscid stably stratified differential rotating fluid for rigid, stress-free or periodic boundary conditions, provided the angular velocity Omega decreases outwards with radius r. At not too small stratification, its growth rate is a fraction of Omega. The influence of viscous dissipation and thermal diffusivity on the instability is studied numerically, with emphasis on the case when d ln Omega/d ln r = - 3/2 (Keplerian case). Strong stratification and large diffusivity are found to have a stabilizing effect. The corresponding critical stratification and Reynolds number for the onset of the instability in a typical disk are derived. We propose that the spontaneous generation of these linear modes is the source of turbulence in disks, especially in weakly ionized disks.	
Tipo: 	Text	
Idioma: 	Inglês	
Identificador: 	http://archimer.ifremer.fr/doc/00253/36469/35013.pdf

DOI:10.1051/0004-6361:200400065

http://archimer.ifremer.fr/doc/00253/36469/	
Editor: 	EDP Sciences	
Formato: 	application/pdf	
Fonte: 	Astronomy &amp; Astrophysics (0004-6361) (EDP Sciences), 2005-01 , Vol. 429 , N. 1 , P. 1-13	
Fonte: 	ESO 2004

info:eu-repo/semantics/openAccess

restricted use