A hydrodynamic validation study of the concept of the mixed foil has been conducted. A mixed foil is a streamlined hydrofoil equipped with a flap or other device which, above a certain speed, can be activated so as to change the flow around the foil into a supercavitating flow. At take-off and at moderate speeds, a mixed foil is operated as a subcavitating foil; at high speeds, it is operated as a supercavitating foil. During high-speed operations, a reduction in the wetted planform area of a mixed foil is proposed. The present study produces a design outline for the mixed foil and identifies essential problems which should be studied in the future. The analysis is illustrated by using hydrofoils with plano-convex sections. The lift-to-drag ratios at takeoff and at 45-knot and 83-knot cruising speeds are obtained.

This content is only available via PDF.
You can access this article if you purchase or spend a download.