SPH Modelling of Spiral Shocks in Viscous and Inviscid Accretion Discs in Close Binary Systems
Abstract
A comparison between an accretion disc model, whose transport mechanisms are driven only by artificial viscosity, and a physically viscous accretion disc model in the same close binary system, is here performed adopting the same binary parameters, the same boundary conditions and the same high gas compressibility. These assumptions mean that artificial viscosity, included in both models, shares together with the physical viscosity as for mass and angular momentum transport in the second disc model. The Smooth Particle Hydrodynamics (SPH) lagrangian framework scheme has been adopted in both models and α_{SS} = 1 has been considered as for the viscous model according to the well known Shakura and Sunjaev formulation. Physical viscosity is represented by the viscous force contribution as a divergence of the symmetric viscous stress tensor in the NavierStokes equation, whilst the viscous energy contribution is given by a symmetric combination of the symmetric shear tensor times particle velocity. Adopting a supersonic particle injection at the inner lagrangian point L1, clear spiral strong shocks develop in the inviscid 3D model. Extended spirals and shock fronts are still present in the viscous accretion disc model, which is larger than the nonviscous one on the XY orbital plane. Characteristics of the two disc structures are discussed.
 Publication:

8th AsianPacific Regional Meeting, Volume II
 Pub Date:
 2002
 Bibcode:
 2002aprm.conf..343L