Abstract: In the construction of a new power system with a high proportion of new energy, the cavitation characteristics of guide vanes and blades in hydropower units, especially pumped storage units under switch condition are quite different from stable condition, and the cavitation development mechanism is worthy of further study. This study examines the flows around a hydrofoil that oscillates in two different modes based on filter correction (FBM) and a Zwart-Gerber-Belamri cavitation model, focusing on the characteristics of flow cavitating evolution and the influences of different modes on the dynamic characteristics of cavitation. The numerical results of the cavitation shapes and velocity vectors around a NACA0015 foil are analyzed, the influencing mechanism of cavity evolution and the hydrodynamic parameters of its oscillating motions are explored. The results show that in the head fixed mode, foil oscillation induces larger cavities and a higher time-average volume fraction of vapor phase than the tail fixed oscillation, and the volume is larger. Under sheet cavitation in the two modes, the overall volume curves of vapor phase are very similar, while they are significantly different under cloud cavitation that differs in form.

Key words: oscillating hydrofoil, cavity evolution, hydrodynamic characteristics, head fixed, tail fixed