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 .