Free-surface water tunnel studies of a family of base-ventilated hydrofoils

This test program is one of a series designed to investigate the properties of base-ventilated hydrofoils. The purpose of this study was to determine the two-dimensional force and ventilation characteristics of an uncambered hydrofoil which could be truncated by removing four removable trailing edge sections. The program was performed at the request of T. G. Lang of the Naval Ordnance Test Station, Pasadena, who in Reference 1 analyzed the possibilities of reducing the cavity drag of base-ventilated hydrofoils by selecting appropriate section profiles and foil base thicknesses. Using a profile developed in Reference 1, it was intended to study the effects of ventilation air flow rate, angle of attack, and the position of the trailing edge cutoff points, and to compare the experimental values of the drag with those predicted from a linearized flow theory.