Numerical Analysis of Cavitation Suppression on a NACA 0018 Hydrofoil Using a Surface Cavity

This study examines the hydrodynamic and acoustic performance of plain NACA0018 hydrofoil and modified NACA0018 hydrofoils (foil with a cavity on suction surface) at a Reynolds number (Re) of 40,000, which is indicative of small-scale turbines and marine applications. A cavity was created on suction side surface at 40–50% of the chord length which is chosen for its efficacy in cavitation control. The present analysis examines the impact of the cavity on lift to drag ratio (L/D) and cavity length at three cavitation numbers (1.7, 1.2, and 0.93) for plain and modified hydrofoils. Simulations demonstrate a significant enhancement of 11% in the lift-to-drag ratio relative to traditional designs. Contrary to earlier observations, the cavity length increases instead of decreasing for the modified hydrofoil. Both steady and turbulent inflow conditions are captured by sophisticated computational techniques that simulate the complex cavity dynamics and flow-acoustic interactions. Experimental validations enhance the numerical results by offering comprehensive evaluations of lift, drag, and acoustic properties. Spectral analysis using Mel-frequency techniques confirms the cavity’s potential to reduce low-frequency flow-induced noise. These findings offer new insights for designing quieter and more efficient hydrofoils and turbine blades.