A discontinuous cavitation model (DCM)

A discontinuous cavitation model (DCM) containing the effects of ambient overpressure, incondensable gas, inertia, viscosity, surface tension, characteristic nuclei size, and characteristic surface speed of cavitation nuclei was proposed based on two approximate local first integrals of the Rayleigh–Plesset equation. Discontinuities caused by sudden cavitation bursting, heterogeneous nuclei distribution, and bubble-induced turbulence can, thus, be roughly represented. It was employed in simulating kinds of cavitation flows. It presented more physical reasonability than the Singhal model (SM) in capturing the vigorous vaporization in the water pool under strong negative ambient pressure. As for hydrodynamic cavitation around the National Advisory Committee for Aeronautics hydrofoil NACA0015, not only large-scale features were obtained as well as the SM, but also, some small-scale structures in the cavitation cloud were presented. For instance, isolated bubbles and their dynamic behaviors, such as inception and collapse, expansion and shrinkage, and breakup and coalescence, were captured. Extra turbulence pulsation, which is correlated with the temporal–spatial distribution of vapor concentration, can also be observed in the cavitation cloud. Moreover, different from the vorticity field obtained by the SM, the surface of the cavitation cloud obtained by the DCM becomes a thick vortex sheet. Moreover, another simulation case with a cavitation number of 0.32 further confirmed its adaptivity in supercavitation flows. Furthermore, by adjusting the parameters (i.e., the fluid density in the phase change layer near the cavitation nucleus) in the DCM, oscillations and waves excited by fierce phase change can be observed in cavitation clouds.