Investigation of hull pressure fluctuations generated by cavitating vortices

The paper describes an ongoing research program at MARIN for the investigation of low frequency hull pressure fluctuations caused by cavitating vortices. Model scale measured hull pressure fluctuations generated by a cavitating vortex on a marine propeller have been analyzed with respect to variations between blade passages. It is shown that these variations have a significant influence on the amplitude spectrum from which it is concluded that the broadband energy content of the spectrum is just as important as the harmonics of blade passage frequency. The collapse and rebounds of the cavitating vortex show very distinct frequency components. These frequencies are reasonably well predicted by a theoretical formulation, obtained by applying the method of stationary phase to the dispersion relation for waves on cavitating vortices.