LAUSR

Shallow hydrofoils are known to produce lower lift in normal operating conditions in comparison with deep hydrofoils. However, the maximum lift capability of shallow hydrofoils at moderate speeds, which is important for transitional regimes of hydrofoil boats, is studied insufficiently. In this work, two-dimensional flow around a high-lift hydrofoil at a moderate Froude number is numerically simulated in a broad range attack angles up to the stall occurrence in both single-phase fluid and in the vicinity of free surface. It is found that nearly the same maximum lift coefficient can be produced by the shallow foil in the modeled condition as by the deep foil, but much higher attack angle is required near the free surface, which also results in larger drag. Additionally, it is shown that higher Reynolds numbers lead to higher lift coefficients, especially at large attack angles.