Analysis of the Body Shape of a Sea Glider using Numerical Simulation and Model Testing

Today Special vessels are used to monitor the underwater environmental conditions and the bed of the seas and oceans. Such vessels are designed and used in different ways. One of these types of vessels is the sea-glider. The body shape of sea-gliders varies based on operating requirements and environmental conditions. They are designed to have very low energy consumption due to the lack of a propeller propulsion system, so they can perform their mission underwater for a long time. These gliders are usually designed to have a floating system, fixed wings, internal moving objects, a ballast pump and a rudder. Therefore, the downward and upward movement of these gliders is controlled by the movement of its internal objects back and forth and its vertical movement (height and depth change) is controlled from floating change from negative to positive and vice versa. Numerical analysis of these gliders is very practical and important in order to better understand the motion control and maneuverability. This paper examines the lift and drag coefficient of a sea-glider at different angles of attack in which fixed blocks play a major role. The study of these coefficients and their changes, which are the main hydrodynamic parameters, have a great impact on how to improve the motor performance and maneuverability of gliders. The glider studied in this paper is Sea-glider, which underwater performance, geometric model in Katia software, static model and numerical analysis in Ansys- Fluent software is done and finally the obtained results are validated with testing results of the model in the towing tank. The analyzes were performed at different angles. At zero-degree angle, the maximum pressure point or stagnation point at the tip of the nose in front of the sea-glider is 2.30 Pascal. The lowest pressure and maximum fluid velocity occur at the junction of the wings to the body and its curvature. The error rate of numerical results compared to experimental results is about 30%, which is reasonable compared to similar studies.