Abstract: The unsteady dynamics of cavitating flows around ahydrofoil and in a cascade hydrofoil are investigated by numerical andexperimental methods. Experiments around a hydrofoil and on a cascadehydrofoil are carried out in a rectangular test section of a cavitationtunnel，and the lift and drag force are conducted and the frequencycharacteristics of lift signals are analyzed. The cavitation model incalculation is Kubota model which can describe the unsteady vortexcavitation accurately; the filter-based turbulence model can capture theunsteady characteristics in the flow more exactly; the reliability of thenumerical model is validated by the experiment of the cavitation tunnel. Theresults show that a good agreement is obtained between the experimental dataand the numerical simulation results. Compared the results around ahydrofoil, the cavitation thickness about the cascade hydrofoil is thinner;the adverse pressure gradient near the wall of the cascade hydrofoil issmaller; the intensity of the re-entrant jet and the velocity gradient inthe mixing field are smaller and the shedding time is longer.