FOCUSING OF THE RAREFACTION WAVE IN A THIN CAVITATING FLUID LAYER WITH A FREE BOUNDARY

摘要

A new method of focusing the rarefaction wave in a one-dimensional axisymmetric formulation is proposed. The method is based on shock wave generation initiated by motion of a piston coaxial with the axis of symmetry with a prescribed pulse profile for the maximum velocities of 20 to 100 m/s and the exponent decay constant up to 10 s. It is found that reflection of the shock wave from the free boundary generates a rarefaction wave propagating toward the axis of symmetry with increasing amplitude, and a cavitation zone is formed and developed behind the wave front.