Numerical investigation of tip-vortex cavitation with a modified cavitation model incorporating the effect of dissolved gas

Tip-vortex cavitation (TVC) is strongly affected by water-quality conditions, yet dissolved-gas effects remain insufficiently represented in the Schnerr–Sauer (S-S) cavitation model. In this study, a modified cavitation model considering the dissolved gas effect is developed to improve the prediction of TVC. Oxygen species transport is considered in both the liquid and gas phases, and the interfacial exchange of oxygen is described based on Henry's law mass-transfer relation, and the released oxygen partial pressure is incorporated into an effective cavitation threshold within the S-S framework. The model is first verified against a plug-discharge experiment for transient oxygen dissolution and then validated for cavitating flow over a Clark Y-11.7% hydrofoil. It accurately predicts dissolved-oxygen evolution and improves the reproduction of cavity morphology and the dominant lift-frequency response. The model is further applied to TVC over an elliptical NACA 16-020 hydrofoil, where the predictions show close agreement with experimental observations. The results indicate that oxygen exsolution is primarily concentrated near the cavity interface, where it increases the local partial pressure of non-condensable gas, modifies the effective cavitation threshold, thereby promoting downstream cavity persistence under the examined conditions. These findings demonstrate that dissolved gas plays an important physical role in the reliable prediction of TVC.