Dynamics of a Spherical Cavity in a Cavitating Liquid with a Continuously Changing Concentration of Cavitation Nurses

An equation was obtained and the problem of the dynamics of the formation and radiation of a quasi-empty pulsating spherical cavity in a cavitating liquid under the influence of the changing speed of sound in the cavitation zone and the concentration of cavitation nuclei was solved for the first time. Data on the dynamics of the cavity, on radiation and the speed of collapse for the spectrum of internal initial pressure values showed that at the maximum concentration of the gas phase, the pulsations differ in the degree of compression. They have almost the same character — after the first collapse, only one half-cycle occurs, reaching different constant equilibrium radii. The condition of equality of pressure in the cavitation zone and inside the spherical cavity at its boundary made it possible for the first time to establish a dynamic relationship between the volumetric concentration (speed of sound) in the cavitation zone and the radius of the spherical cavity. When calculating and constructing a solution, the condition changes, according to which the initial size of the cavity takes on a value corresponding to the value of the initial pressure. The dependences of the radiation amplitude over the entire range of applied pressures were plotted. It turned out that the radiation amplitude increases by 5 orders of magnitude when the initial pressure in the cavity changes by 3 orders of magnitude from 10^–2 atm to 10^–5 atm.