Experimental research progress of hydrofoil tip vortex cavitation

As a typical vortex cavitation phenomenon, Tip Vortex Cavitation (TVC) occurring on the propellers (or duct propellers) and hydro-turbines has been widely investigated in experiments. To figure out the research orientations and the key problems in the near future, experimental research progress and results about the three stages of TVC, that are inception, development and collapse, are summarized to provide reference for further studies. On the inception of TVC, analysis of vortex dynamics of the tip flow field is conducted to get preliminary acquaintance with mechanics of its inception under various phase transformation conditions of bubble nuclei, low pressure and action time of low pressure, based on vortex theoretical models and experimental measurement technology. On the development of TVC characteristiced by a sharp increase of the radiation noise, research on the morphology of TVC and characteristics of the corresponding radiation noise is carried out for a better understanding of the mechanism of the development and radiation noise of TVC, in combination of high-speed photography of the morphology and acoustic signal acquisition of TVC. The collapse of TVC is only mentioned briefly, because few attention is paid to this issue as it can hardly cause vibration and erosion on hull structures. An accurate prediction of the inception of TVC in practice is still an open question though some progress is made in the fundamental research of TVC. How to quantify the scale effect of the vital parameters, such as load, Reynolds number and water quality, and how to improve the incipient prediction formula of TVC are problems still to be solved.