SELF-SIMILAR SOLUTIONS IN GAS-DYNAMICS WITH EXPONENTIAL TIME-DEPENDENCE

Self-similar gas flow with similarity coordinate xi=re(-/+t), exponent ial in time, is investigated for plane, cylindrical and spherical geom etry. The underlying Lie group symmetry is pointed out and also how it is obtained from flow with power-law self-similarity (xi=r/\t\(alpha) ) in the limit alpha-->infinity. Six distinct types of solutions are d erived and plotted in r-t coordinates. They are characterized by steep density gradients. Also, solutions with strong shock boundaries are d iscussed. A completely analytical solution is presented, related to Se dov's solution of a strong point explosion. (C) 1997 American Institut e of Physics.