The self-similar problem about a collapse of an empty cylindrical or spherical cavity in compressible fluid with adiabatic exponent γ is considered. Two possible variants of the flow after collapse are discussed. The variants are connected with the entropy behavior through the outgoing shock. The calculations show that the main difference in the flow quantities behavior at reflection stage have a quantitative character. Outgoing shock compression ratio, characterized by relation ρ2/ρ1, decreases for both variants of the reflection when γ is increase.
