Hydrodynamics and control of an autonomous underwater vehicle equipped with a vectored thruster

In this study, a laminar flow hull shape is implemented on an Autonomous Underwater Vehicle (AUV), with boundary layer suction at the aft end of the hull to prevent separation. The hull shape has the largest diameter of the vehicle near the aft end of the hull resulting in an accelerating flow over the majority of the hull's surface. The problem of axially symmetrical flow around the AUV is solved using a potential flow analysis. A finite difference algorithm evaluates the stream function, leading to the computation of fluid velocity and pressure fields. The boundary layer characteristics are analyzed to predict the risk of separation. The numerical results are compared with laboratory measurements of the flow using a Particle Image Velocimetry system. Fuzzy Logic Sliding Mode Controllers are implemented to control the vectored thruster vehicle, and are simulated using a six-degree of freedom dynamic model of the vehicle.