Abstract: To study the cavitation mechanism in the cavitation flow field around a hydrofoil, by using high-speed degrees photography, the partial and cloud cavitation at an angle of attack of 10, and simulating with a corrected RNG k-ε turbulence model is observed. And the structure and evolution process of the sheet and cloud cavitation of unsteady cavitation flows is analyzed. The results show that there is little fluctuation near the boundary of the hydrofoil under the sheet cavitation. The cloud cavitation can be divided into two areas, the former part of main body, adhering to the hydrofoil of the suction surface stably, and its inner part is filled with water vapor. The second part of cavitation is vacuolus appendage and it is periodic and unsteady two-phase movement area. Development of cavitation is accompanied by pressure fluctuations. The pressure coefficient under the surface is hardly effected by cavitation, and the pressure coefficient at the surface have small fluctuations in nearby cavitation numbers.

Key words: Cloud cavitation, High-speed degrees photography, Hydrofoil, Numerical simulation, Partial cavitation, Pressure coefficient, Coupled chains Spatial mechanisms Mobility Screw theory