Several axi-symmetric surfaces or revolution are introduced as possible cowlings to be attached to an existing spherical buoy to create a streamlined buoy shape that minimizes the drag force and reduces vortex shedding whilst the buoy remains stable and self-aligning in tidal flows. Analysis of the proposed shapes is carried out by CFD software and a proposed shape is found that reduces the drag force to 25% of that of the original spherical buoy. As well, analysis of data from an axi-symmetric airship Akron is performed to investigate lift, drag, pitching moment, pressure distributions and centers of effort of surfaces of revolution as functions of angle of attack.
National Research Council of Canada. Institute for Ocean Technology