Wall Wettability Control of Cavitation Patterns and Stability

This study investigates the role of wall wettability, characterized by the wall contact angle (WCA), in controlling cavitation dynamics and stability around a Clark Y hydrofoil. High-fidelity Large Eddy Simulations (LES) coupled with a dynamic contact angle model were employed within the OpenFOAM framework to explore WCAs ranging from hydrophilic ($0^\circ$) to superhydrophobic ($160^\circ$) under distinct cavitation numbers ($\sigma = 1.6$, $0.8$, and $0.4$), representing incipient, cloud, and supercavitation regimes, respectively. The results show that increasing WCA consistently promotes earlier cavitation inception, thicker cavity development, and greater flow unsteadiness. For $\sigma = 1.6$, higher WCAs led to smaller, detached vapor bubbles and localized pressure fluctuations. At $\sigma = 0.8$, superhydrophobic surfaces caused more extensive vapor structures, intensified shedding dynamics, and stronger pressure fluctuations. For $\sigma = 0.4$, high WCAs facilitated stable, wall-adhered cavities that suppressed re-entrant jet activity and reduced unsteady loading. These findings demonstrate that surface wettability serves as an effective passive control mechanism for tailoring cavitation behavior and optimizing flow stability in engineering applications.