Assessment of Numerical Models for Unsteady Cloud Cavitation and Erosion Potential Around Different Hydrofoils

The accuracy of the numerical simulation of unsteady cloud cavitation around a hydrofoil depends on the combination of the cavitation model, the Reynolds-Averaged Navier–Stokes (RANS) turbulence model and the exponential coefficient n of the Reboud’s correction. To assess the influence of such choices, three turbulence models, three cavitation models and two values of n have been combined to predict the shedding frequency and the morphology of cloud cavitation around the NACA65012 and NACA0009 hydrofoils. The comparison with analogous experimental results obtained in a cavitation tunnel indicates, firstly, that the same numerical set-up differs in accuracy depending on the hydrofoil geometry. Secondly, within the scope of the two tested hydrofoils and corresponding flow conditions, the Shear Stress Transport (SST) turbulence model and the value of n = 10 appear to be more accurate and more robust for all tested cases. And finally, the predicted shedding frequency is more sensitive to the selection of the turbulence model than to the cavitation model. If an erosion model is implemented, then it is found that the predicted potential energy distribution of the cavitating flow is sensitive to the selected cavitation model. In our case, the Sauer model gives a more accurate distribution and intensity of erosion power than the rest of the cavitation models.