Stall characteristics of the submerged hydrofoil section

Abstract

A NACA 4412 hydrofoil section was held stationary in an open flume containing streaming water. Pressure distributions were measured at 6 different submergence depths, 4 different speeds and 7 different angles of attack by 30 pressure taps arranged around the center of the hydrofoil span. These pressure distributions were integrated to obtain the lift and drag on the section.
In §3, the effect of the submergence depth on the pressure distribution was examined and then discussed the flow characteristics from the standpoints of the gravity effect, inertia effect, boundary layer separation, and ventilation.
In §4, two types of stall, ie laminar flow separation and turbulent flow separation were clarified from the standpoint of the resultant force at each submergence depth.
In §5, the effect of the submergence depth on the lift and drag was examined and, in particular, the stall characteristics were fully discussed.
In §6, the similar law was considered in detail for the shallowly submerged hydrofoil section characteristics and also the scale effect was examined.