Digital particle image velocimetry measurement and analysis of velocity distribution in cavitating flows around a hydrofoil

The time-averaged velocity distributions in flows around a Hydronautics foil were obtained by means of a digital particle image velocimetry (DPIV) system. The measured results show that velocity distribution in the whole flowing field depends on development of the cavitation structures with decreasing of the cavitation numbers; the high-fluctuating region with lower velocity corresponds to the cavitation area; the lowest velocity distribution in the cavity core behaves more evenly, and becomes smaller as moving downstream; the main-stream velocity distribution experiences such developing process as the even-the fluctuant-the even gradually behind the hydrofoil; the fluid velocity distribution in the cavitation region, corresponding to the front of the foil's suction surface, approaches that of the main stream region, and the fluid velocity distribution of the other cavitation region is lower, in the supprcavitation stage.