Bio-inspired leading-edge deformation for cavitation mitigation and enhanced hydrodynamic performance on hydrofoils

Cavitation severely limits the efficiency, durability, and stealth of marine lifting surfaces. Inspired by the efficient “nose-drop” morphology of cetaceans, this study investigates a passive leading-edge deformation strategy on a benchmark hydrofoil. Two-dimensional RANS and three-dimensional LES simulations quantify the effects of deformation region (x₀/C) and nose-drop ratio (d₀/x₀) on pressure reconstruction and cavity dynamics. Results indicate that increasing these parameters alleviates the suction-side pressure peak and smooths the adverse pressure gradient, thereby promoting flow attachment. Consequently, cavity thickness and volume decrease rapidly, achieving complete suppression beyond critical thresholds (x₀/C = 0.3 at σ = 1.41; x₀/C = 0.5 at σ = 1.25). Crucially, this suppression is accompanied by significant drag reduction and lift enhancement, improving cavitation resistance with minimal hydrodynamic trade-offs. The underlying mechanism relies on severing the re-entrant jet feedback loop that drives sheet and cloud shedding instability. The proposed strategy thus offers a simple, robust, and passive approach for enhancing the operational envelope of marine propulsion systems.