Analysis of Autonomous Underwater Gliders Motion for Ocean Research

Abstract

Underwater gliders, a type of highly efficient underwater vehicle which uses gravity and buoyancy for propulsion, has been studied for a long time during the last 3 decades. This paper describes the development of the principle dynamic models of a general underwater glider, including hydrodynamic forces and buoyancy effects. The numerical analysis model was developed for the underwater glider motion. Dynamic forces equations including the model’s buoyancy, gravity, and hydrodynamic forces in gliding are derived. Gliding velocities with changes of the net buoyancy are compared. The numerical method was used to calculate the hydrodynamics coefficient of the glider. Dynamic characteristics of the Seaglider and SLOCUM have been used as validation objects for the numerical method. The glide angle is merely the function of the lift/drag ratio and has no relation to the net buoyancy. The gliding velocity would increase when the buoyancy increases.