Vortex characteristics in cavitating flows around a hydrofoil

To explore the development of vorticity distribution in cavitating flow field, the cavitating flow fields around a hydronautics foil were measured by means of a digital particle image velocimetry (DPIV) system and a high-speed video camera. The results show that the changes of vorticity distributions in the flow fields depend on the development of cavitation structures. Most vortices can be seen near the shear-layer area in all cases, and behave as vorticity bands. With the decreasing of cavitation numbers, the vorticity value lowers since there is no large grad of the velocity in the cavitation area. The upper and lower vorticity bands approach each other and extend downstream, while the inceptive position of the lower one moves downstream.