Measurements on Fully Wetted and Ventilated Ring Wing Hydrofoils

Abstract

Force measurements and visual observations were made in a water tunnel on fully wetted and ventilated flows past a family of conical ring wings having a flat plate section geometry. The diameter chord ratio was varied from one to three, at a fixed total included cone angle of 12 deg. The fully wetted flows all exhibited separation from the leading edge except for the largest diameter-chord ratio, a result which has been attributed to excessive cone angle. The effect of ventilation is to reduce markedly the lift curve slope. Pressure distribution measurements were also made under ventilating conditions for one member of this series. The effect of ventilation over only a portion of the circumference of the ring was also briefly investigated; large cross forces were developed by such ventilation.