Numerical simulations of a multi-arm gaseous configuration in a global two-arm spiral gravitational field

The results of numerical simulations of supersonic, gas-dynamical processes occurring in the disks of spiral galaxies are presented. Qualitative and quantitative pictures of morphological features in the structure formed by a two-armed gravitational potential are given. A gas-dynamical interpretation of a quasi-stationary configuration containing two shock fronts separated by a contact discontinuity is discussed. This type of supersonic configuration with three jumps can form and produce a spiral pattern with six arms displaying global two-fold symmetry. An economical method has been used to calculate the complex, non-stationary, supersonic gas flows using a fully conservative difference scheme to solve the appreciably divergent gas-dynamical equations in the Euler variables in an axially symmetric approximation. © 2014 Pleiades Publishing, Ltd.