Froude Number Effects on Two-Dimensional Hydrofoils

The performance of a two-dimensional hydrofoil of arbitrary camber, moving at arbitrary Froude number at a constant depth below a free surface, is considered. The treatment is based upon the use of singularity distributions and thin foil theory. By assuming an appropriate series form for the vortex distribution representing the hydrofoil, it is shown that the problem can be reduced to the solution of a set of linear algebraic equations. These are solved by a collocation procedure. Numerical results for the performance characteristics are then given for several hydrofoil configurations, submergence depths, and Froude numbers. These indicate that operation at Froude numbers greater than about ten is practically equivalent to operation at infinite Froude number. However, at lower values of the Froude number and for all the configurations considered, Froude number effects are important, even at submergence depths of several chord lengths.