On cavitation caused by tip clearance of a flat-plate hydrofoil

This research integrates experimental visualization via high-speed photography with numerical simulations, leveraging large eddy simulation and the Schnerr–Sauer (S-S) cavitation model, to examine cavitation dynamics on a flat-plate hydrofoil across a range of tip clearance settings. We identify three distinct cavitation patterns caused by tip clearance (CT) in terms of the flow structures and interactions of tip leakage vortex cavitation, tip separation vortex cavitation (TSVC), and shear layer cavitation. The flat-plate hydrofoil demonstrates stronger TSVC and more pronounced vortex interactions compared to National Advisory Committee for Aeronautics 0009 hydrofoils. A phase diagram is established to predict the cavitation patterns of CT under different operational conditions of the cavitation number σ and the angle of attack α. We also observe a downwash effect from the vortices, influencing the cavitation length on the suction side of the hydrofoil. The findings are significant for optimizing hydrofoil designs in fluid machinery where effective cavitation management is critical.