Towing tank experiments on underwater gliders for varying angles of attack

Autonomous Underwater Gliders (AUGs) are a type of Underwater Vehicles that use a buoyancy engine to vary their weight and move with the help of the Lift and Drag forces from the body and the wings. The longitudinal saw-Tooth path and the spiral path for turning are the characteristic maneuvers for the glider. The hydrodynamic forces and moments participate in the glider maneuverability equations as Hydrodynamic Coefficients (HDCs). The methodology of estimating the glider HDCs includes numerical and experimental methods. This paper describes the experimental method for the determination of HDCs. The experiments are undertaken in a towing tank with measurement of forces and moments carried out on a candidate underwater glider. The model is towed at different speeds at each angle of attack with measurement undertaken using a multi-Axis load cell. The data thus extracted is used for the estimation of the lift and drag coefficients. The results will be useful for establishing maneuvering parameters of the underwater glider being studied.