DESIGN OF DELTA WING AUTONOMOUS UNDERWATER GLIDERS FOR LONG TERM SUSTAINABLE AND STEALTH RECONNAISSANCE USING NUMERICAL STUDIES

Abstract

Autonomous Underwater Gliders (AUGs) are a unique source of collecting oceanographic data for varying depths with longer endurance than other types of unmanned underwater vehicles. The buoyancy-driven propulsion mechanism assists in diving deep into the ocean, collect data, resurface in saw-tooth and spiral motions. There have been various hull-forms introduced for this purpose starting from - Torpedo hull, XRay Flying-Wing Glider, etc., all of which have seen an improved understanding of the hydrodynamics associated with the hull-form of the gliders. The saw-tooth motion represents the glider's capacity to cover larger distances with a smaller angle of attack, thereby achieving an increased range for the same power included within the hull batteries. In this paper, a design study of delta wing hull-forms, which are proven to have better longitudinal motion characteristics, is proposed to arrive at a preliminary hull form that can be used for long term reconnaissance missions, remaining in stealth to assist submarines with valuable data. Delta wing hull forms are varied using different NACA sections, and numerical analysis of the obtained hull forms is performed to arrive at the hydrodynamics; namely, the drag, lift forces and coefficients for varying angles of attack, using commercial CFD software – StarCCM+. These results are then compared against each other to derive the preliminary hull form for further study on better longitudinal motion characteristics, thereby using less power for its motion underwater.