Numerical investigation of the cavitation effect on natural frequencies of a hydrofoil

Abstract

The added mass effects on a NACA0009 hydrofoil under cavitation conditions determined in a cavitation tunnel have been numerically simulated using finite element method (FEM). Based on the validated model, the effects of averaged properties of the cavity considered as a two-phase mixture have been evaluated. the simulation results point out that the average properties of the cavity, considered as a mixture of vapor/water, have a significant effect on added mass coefficients and mode shapes. These effects appear to be more important for higher modes of vibration. For instance, the first torsion mode can evolve towards the second bending mode when reducing the cavity void ratio from 1 to 0.9.