Dynamics of cavitating layer on a surface of quasi-empty cavity in a real heterogeneous liquid

Abstract

The state dynamics of a heterogeneous medium surrounding the spherical cavity is considered, using the multi-phase mathematical model with an incompressible liquid component. The heterogeneous medium contains 1.5-micron bubbles with a density of 106 cm−3. At t = 0, the pressure in the cavity is sharply decreased up to p (0) values forming instantly the dynamically changing decompression wave in the surrounding medium. Numerical analysis allowed to find the significant influence of p (0) values on the dynamics of the cavitating layer on the cavity surface. When p (0) = 10−2 MPa, approximately 20 pulsations of bubble radii and their internal pressure are observed during the collapse time of 1 cm cavity (T is 0.9 ms). Most of them reach only its initial state with a pressure about 0.1 MPa. But at approaching to the time moment close to T value, a few pressure pulsations demonstrate the cumulative effect of over-compression up to the pressures of 0.6, 1.8, and 3 (in log-scale). The letter means that cavitating boundary layer accumulates the energy of high density. When the p (0) = 10−4 MPa, only one pulsation synchronous with the cavity collapse as well as the over-compression effect are observed. [Work supported by RFBR, grant 15-05-03336.]