A Numerical Design Study of Fully Cavitating Hydrofoil Sections Having Prescribed Pressure Distributions.

摘要

Results of a study of fully cavitating hydrofoil sections are reported. All calculations are based upon the linearized theory of cavity flow in two dimensions. This report is the first detailed exploration of the consequences of the general inverse theory which permits the designer to specify the design values of the lift coefficient, cavitation number and the thickness of the upper surface of the cavity at the profile trailing edge as well as the shape of the pressure distribution on the wetted surface. The ordinates of the upper cavity contour and the wetted surface contour are calculated. The design angle of attack, the cavity length, the drag coefficient and the moment coefficient are also calculated. It is found for almost any cavitation number and any design lift coefficient that if the center of pressure is placed as closely as possible to the profile leading edge the resulting profile will have the most favorable lift-to-drag ratio. The study also includes off-design calculations, in accordance with the direct theory of cavity flows, to determine cavity interference iwth the upper nonwetted surface of the profile and the hydrodynamic forces of particular designs. (Author)