Dynamic stability of positively buoyant submersibles : vertical plane solutions.

Abstract

This thesis analyzes the dynamic stability of positively buoyant submersibles. Six degree -of- freedom equations of motion are used to compute steady state behavior with motion restricted to the vertical plane. Steady state solutions are analyzed for various conditions of buoyancy including changes in (1) the amount of excess buoyancy, (2) the location of the center of buoyancy, (3) the location of the center of gravity, as well as (4) the deflection of bow and stern planes. The equations of motion are then linearized around these steady state solutions to predict dynamic response in the vertical plane. The stability of each solution is then determined by eigen value analysis. The study then expands the analysis to include all six degrees of freedom (i.e., include stability analysis in the horizontal plane). Finally, numerical integration methods are used to verify the results.