Linear analysis of rotating cavitation by a singularity method

A linear stability analysis of rotating cavitation in a flat plate cascade was carried out by a singularity method based on the closed cavity model allowing the cavity length freely to change. This analysis does not need any information about the unsteady cavitation characteristics such as mass flow gain factor and cavitation compliance as inputs. It is fuond that there are many solutions of characteristic equations. One of them corresponds to the forward rotating cavitation, which is often observed in the experiments. The propagation velocity ratio of this mode agrees with that in experiments, while the onset range is larger than that in experiments. The second solution corresponds to the backward mode, which was also found in semi-actuator disk analyses and identified in an experiment. Other solutions of characteristic equation are found to be associated with the higher order modes of cavity shape fluctuation, which have not yet been identified in experiments.