Lifting-Line Theory of a Supercavitating Hydrofoil in Both Vertical and Spanwise Shear Flow. 2nd Report. Application to Partial Cavitation.

Abstract

The existing lifting-line theory for a supercavitating hydrofoil in both vertical and spanwise shear flow between two parallel planes is applied to partial cavitation in the same flow condition. A lifting-line equation is derived from combining the assumption holding lift coefficient two-dimensional at any spanwise position with the up-wash velocity distribution induced along a lifting-line. The hydrofoil for the numerical example is flat in section, rectangular in planform, and 5 degree in attack angle. Effects of two kinds of shear parameter, cavitation number, and taper ratio on local life coefficient, total lift coefficient and induced drag coefficient are clarified through the numerical calculations. The cavity length distribution is obtained on the basis of the assumption holding the pressure within cavity two-dimensional at any spanwise position.