Numerical Study on Unsteady Characteristics of Cavitation Flow Generated from Hemispherical Model

To further study the unsteady characteristics of cavitation flow,a new mathematical cavitation model based on Rayleigh-Plesset equation was given out.Both steady and unsteady cavitation flow generated from hemispherical cylinder were simulated numerically by using the new model in 2D axial symmetrical coordinates.The successful application and validation of the new model show that the condensation occurs when the bubble expands and evaporation happens when the bubble collapses.It can be seen from the analysis of the experiments and the numerical simulations that,according to the cavitation number,the cavitation flow is divided into three types,i.e.supercavitation flow,secondary cavitation flow and weak cavitation flow.Due to the unsteadiness,each type of cavitation flow corresponds to different model coefficients.The new cavitation model can successfully capture the unsteady details of the cavitation flow,and it is helpful to further study the mechanism of cavitation.