Non-linear theory for supercavitating foil

This paper presents the non-linear theory of a supercavitating foil section, where the transient flow model is applied. The calculated model is based on the Hess & Smith method. The shape of cavity was obtained by the iteration.The calculated result of a cavitating flat plate agreed well with the exact solution by Wu. The theory was applied to the several cavitating foil sections and compared with experiments. The results agreed well with experiments for the supercavitating as well as partially cavitating conditions except for the following cases;(1) For the foil whose trailing edge is open, the effect of cavity from the trailing edge should be taken into consideration. Therefore, it is necessary to make the pressure of the trailing edge be the same as the pressure in cavity.(2) Appropriate modification is indispensable for the foil with cup at the trailing edge. In this case, the separation at the trailing edge of back side of the foil might be important factor for this revision.The theory has been extended to the foil between two parallel walls, and the cascade.