Numerical Study on the Hydrodynamics of Flying Wing Autonomous Underwater Gliders for Shallow Water Maneuvering

Autonomous Underwater Gliders are buoyancy propelled form of underwater oceanographic sampling platforms which have been used for the past few decades. They are continuing to grow as they are being integrated into the underwater and surface network of vehicles and platforms for various purposes vis-a-vis reconnaissance, research data collection, coastal survey and so on. The major distinctive motions of the glider include the Saw-tooth (a surface-dive cycle using the variation in the buoyancy and its wings) and Spiral maneuvers. The glider motion in shallow waters relies on the depth-limited maneuvering capability of the glider. So, the saw-tooth motion plays a definitive role and needs to be studied. This paper focuses on the saw-tooth motion of Flying Wing Underwater Gliders. Flying Wing Gliders are typically known for their high lift capacity during its motion underwater. The appendages on the glider influence its motion and stability. Hence, the effect of the vertical wing on such glider bodies provides interesting results which are discussed as part of this paper. The main hull of the flying wing glider is a tapered NACA0018 section [1]. Four types of vertical wing sections are used for modelling this glider i.e., Flat-plate and NACA0012; each of which further has a variation in the span of the wing (120 mm and 600 mm). These 4 glider hull models are numerically modelled in StarCCM+ and the hydrodynamic forces are obtained for varying angles of attack from -15 to 15 degrees, to analyze the effect of the vertical wing on the lift/drag ratio of the body