Bhattacharjee, Jayanta K.Ray, Arnab K.2012-03-062012-03-062007-07-12http://hdl.handle.net/11007/676A first-order correction in the -viscosity parameter of Shakura& Sunyaev has been introduced in the standard inviscid and thin accretion disc. A linearised time-dependent perturbative study of the stationary solutions of this “quasi-viscous” disc leads to the development of a secular instability on large spatial scales. This qualitative feature is equally manifest for two different types of perturbative treatment — a standing wave on subsonic scales, as well as a radially propagating wave. Stability of the flow is restored when viscosity disappears.enAccretionAccretion disks— hydrodynamics— instabilities —methodsAnalyticaArticle