A Supercavitating Hydrofoil with Mechanical and Jet Flaps Beneath a Free Surface

The flow around a supercavifating hydrofoil equipped with both mechanical and jet flaps, moving beneath a free surface, was analyzed by second-order theory, and the method of matched asymptotic expansions was used to solve the governing integro-differential equation. Hydrodynamic forces which are valid up to the second order of small angles of foil incidence and of jet deflection are determined by asymptotic expansions in terms of the jet-momentum coefficient. Moreover, it is found that Oba's correction factors are not reasonable.