Numerical simulation of accretion discs in close binary systems and discovery of spiral shocks

The history of hydrodynamic numerical simulations for accretion disks in cl ose binary systems is reviewed, in which emphasis is placed, in particular, on the facts that spiral shock waves were numerically found in 1986 by res earchers including one of the present authors and that spiral structure was discovered in IP Pegasi in 1997 by Steeghs et al. The results of our two a nd three-dimensional numerical simulations in recent years are then summari zed, with comparison being made with observations.