A fundamental study of disappearance phenomenon of partial cavitation on the NACA 16012 hydrofoil

For the purpose of understanding of the basic characteristics of cavitation, a number of studies have been conducted using the hydrofoil. An experimental study using NACA16012 hydrofoil was conducted in order to investigate the relationship between cavitation and boundary layer. In the study, it was reported that partial cavitation disappeared in spite of decreasing cavitation number. The authors have reproduced the disappearance phenomenon using the same hydrofoil in the previous study at Tohoku University. Details of the disappearance phenomenon have not been described in the article, and research related to the phenomenon has never carried out and clarified by other researchers. Therefore, in the present study, reproduction experiment of the disappearance phenomenon is conducted with the cavitation tunnel at Kyushu University using NACA16012 hydrofoil and in order to clarify the mechanism of the disappearance phenomenon, lift and drag force and Pressure distribution is measured in non-cavitation condition. As the experimental result, the disappearance phenomenon is observed and the boundary layer characteristics are different from other region the cavitation disappearing phenomenon occurs. In addition, by analyzing the Pressure fluctuation at downstream of the hydrofoil, it was found that the disappearance phenomenon is observed in a certain frequency bands of cloud shedding.