The structure analysis about the cavitation flow around the cascade hydrofoil by numerical and experimental study

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