Experimental study of coupled cavitation–hydroelasticity interaction in hydrofoils with passive vortex-generator control

Unsteady cavitation on hydrofoils generates strong pressure fluctuations that couple with structural deformation, yet the influence of passive control on three-dimensional hydroelastic dynamics remains insufficiently resolved. This study experimentally examines how a wedge-type leading-edge vortex generator (VG) alters cavitation morphology and structural response on the National Advisory Committee for Aeronautics (NACA) 0015 hydrofoils. Three models, including a rigid stainless-steel hydrofoil, a flexible polyvinyl chloride hydrofoil, and a flexible hydrofoil equipped with a wedge VG, were tested across various cavitation conditions at two Reynolds numbers. High-speed imaging system captured the evolution of partial and cloud cavitation, while stereo digital image correlation provided full-field time-resolved deformation and modal content. The results reveal that the original flexible hydrofoil exhibited re-entrant jet-driven cloud shedding and a narrow lock-in region, where the shedding frequency synchronized with the first bending mode. In contrast, the hydrofoil with a VG generated streamwise vortices that disrupted large-scale cloud formation, shifted shedding to higher and less energetic frequencies, substantially reduced cavity volume, and eliminated resonance. These findings clarify how leading-edge passive control modifies cavitation–structure coupling and provide insights for designing hydroelastic cavitation mitigation strategies.