Oscillations of the slender supercavitating hydrofoil near the free surface (Q2755198)

A system of integral equations for slightly disturbed flow around supercavitating and ventilated oscillating hydrofoils near the free surface is obtained. A method to calculate the time dependence of unsteady cavity length by means of numerical solution of the nonlinear equation for balance of gas mass in a cavity (or the equation for pressure to be constant in vapour supercavities) is proposed. It is shown that the approach to a free surface results in decreasing relative amplitudes of oscillations of the cavity length and hydrodynamic forces. Taking into account the variable cavity length leads to smoothing frequency responses in comparison with calculations when the cavity length is constant.