  We perform 2D and 3D numerical simulations of an accretion disc in a close
binary system using the Simplified Flux vector Splitting (SFS) finite volume
method. In our calculations, gas is assumed to be the ideal one, and we
calculate the cases with gamma=1.01, 1.05, 1.1 and 1.2. The mass ratio of the
mass-losing star to the mass-accreting star is one. Our results show that
spiral shocks are formed on the accretion disc in all cases. In 2D calculations
we find that the smaller gamma is, the more tightly the spiral winds. We
observe this trend in 3D calculations as well in somewhat weaker sense.
  Recently, Steeghs, Harlaftis & Horne (1997) found the first convincing
evidence for spiral structure in the accretion disc of the eclipsing dwarf nova
binary IP Pegasi using the technique known as Doppler tomography. We may claim
that spiral structure which we have discovered in numerical simulations before
are now found observationally.
