Large eddy simulation of cavitating flow around a pitching hydrofoil

Abstract

This numerical investigation employs advanced computational fluid dynamics techniques to examine the intricate physics of cavitating flows around a pitching NACA 66 hydrofoil. Unsteady simulations are conducted using both large eddy simulation (LES) and K-Omega SST turbulence models. The pitching motions range from 0 to 15°, encompassing four cavitation numbers (3.25, 3.5, 3.75, 4) and a Reynolds number of 750,000. The study comprehensively analyzes various flow field characteristics, including pressure distribution, velocity, vorticity, shear stress, vapor volume fraction, and turbulence kinetic energy. The kinematics of pitching significantly influence hydrodynamic loads and the surrounding flow structures in cavitating conditions. Flow visualizations illustrate the evolution of sheet/cloud cavitation, reentrant jet, and vortex dynamics throughout a pitching cycle. Notable findings demonstrate the impact of cavitation number on cavity shape and the relationship between angle of attack, reentrant jet location, and vortex size. Additionally, negative vorticity dilatation is observed to be correlated with cavity size.