NUMERICAL ASPECTS OF THE SMOOTHED PARTICLE HYDRODYNAMICS METHOD FOR SIMULATING ACCRETION DISKS

The derivation of the Smoothed Particle Hydrodynamics (SPH) method is reviewed. Ln particular, the problem of second-order derivative terms is investigated. Applying these considerations to the Navier-Stokes eq uations, a physical viscosity is constructed which can be used to perf orm simulations of viscous fluids within the framework of SPH. With su ch a viscous stress tenser the energy balance and the angular momentum conservation for the particle and the continuum representations are c ompared. An SPH code based on these results is tested on different pro blems, especially on an analytically solvable problem, namely the spre ading of a ring of gas moving with Keplerian speed around a point mass . Additionally, some examples for the dynamics of accretion disks in c lose binary systems are presented. Finally, the efficient implementati on of this SPH code is discussed in some detail, in particular by a co mparison between scalar and vector computers.