The viscous gas ring as an astrophysical test problem for a viscous SPH-code

We present the general analytic solution of a viscous gas ring around a central mass. This solution is used to test a further development of the smoothed particle hydrodynamics (SPH) algorithm, which is capable of simulating problems with physical viscosity (here: with kinematic viscosity). We discuss some SPH simulation results and conclude some fundamental properties of the algorithm.