Cavity Shapes for Circular Disks at Angles of Attack

Abstract

The shape of the cavity formed in ;·rater by a circular disk at an angle of attack is derived. The empirical evaluation is based on experimental data obtained with air cavities in the Free Surface Water Tunnel. The effects of model size, free stream velocity and cavitation number on cavity shape are presented. The profile shape of the cavity is assumed to be composed of two superposable phenomena: (1) the cavity shape without gravity effects (2) the displacement of the cavity due to gravity An empirical relation is obtained for the buoyant displacement of the cavity centerline. A quasi-elliptical equation is derived which accurately describes the shape of the cavity about its centerline for the disk at zero angle of attack. The equation is modified and applied to the profile shape of a cavity formed by a circular disk at angles of attack up to 30 degrees. All experimental data are presented in both graphic and analytic form.