Supercavitating Cavity Observations by Means of Laser Velocimeter

The behavior of supercavitation as well as of cavitation, especially near the separation point, were carefully observed in a two-dimensional subcritical flow around a cylinder with and without ventilation. Since supercavitating flow generally detaches from the separation point abruptly, the assumption “smooth separation” often applied is evidently unsatisfactory. There is a transient region, where a kind of supercavitation and of subcavitation can be alternately observed. Outside the immediate neighborhood of the separation point, the flow features are uniquely expressed by σc based on cavity pressure both with and without ventilation, while within that neighborhood, there arise some different features due to ventilation.