“…At that time, however, a direct numerical simulation of the §ow in a hypersonic shock tunnel was impossible because of limitations of computers£ capabilities. The ¦rst steps on the computational simulation of the gas §ow in a shock tube with an adjacent convergent-divergent nozzle were made, apparently, in the very late 1960s (see, e. g., [2]). Since then, many separate aspects of the gas §ow in a shock tube and in nozzles have been investigated numerically.…”