Lifting-Line Theory for Supercavitating Hydrofoil in Shear Flow. (Continuing Report, Application to Partial Cavitation).

Abstract

An existing lifting-line theory for a supercavitating hydrofoil in spanwise shear flow between parallel plane walls is applied to partial cavitation in the same condition. A lifting-line equation is derived from an assumption holding two-dimensional at any spanwise position, and the method of solution of the lifting-line equation is applied, in which an eigenvalue problem of the Sturm-Liouville type should be solved. The method to obtain the cavity spanwise distribution, in which the solution of type lifting-line equation is used, is also applied. The wing for the numerical example is flat in section, rectangular in planform, and 5 degrees in attack angle. Effects of the main stream velocity profile, aspect ratio and cavitation number on local lift coefficient, total lift coefficient and induced drag coefficient for force characteristics, and on spanwise distribution in cavity length and its three-dimensional effect for cavity characteristics are clarified.