A Model of Joint Collapse of Cavitation Bubbles Located on a Spherical Surface

A combined model of joint collapse of cavitation (vapor) bubbles located on a spherical surface has been developed in the case the distance between the bubbles is sufficiently large, so that the influence of their deformations and displacements can be neglected. The efficiency of this model results from the fact that it combines the advantages of the DNS and particle models. In particular, the dynamics of the vapor in the bubbles and the surrounding liquid in the layers R-i <= r(i) <= R-i(*) (R-i is the radius of the ith bubble, r(i) is the distance to its center, R-i(*) similar to R-i at the beginning of collapse) is simulated by a DNS model. In that model, the vapor and liquid dynamics is governed by the gas dynamics equations. The liquid viscosity, the thermal conductivity of both fluids, the evaporation and condensation on the surfaces of bubbles are taken into account, wide-range equations of vapor and liquid state are applied. Outside the regions r(i) <= R-i(*), the liquid dynamics is governed by the generalized Rayleigh-Plesset equations for the interaction of "bubbles" with the radii R-i(*). In those equations, weak compressibility of the liquid is allowed for. Using the combined model, some features of the collapse of identical cavitation bubbles located in water at the vertices of regular polyhedra have been revealed, depending on the number of bubbles, the liquid pressure and temperature.