Experimental and numerical analysis on two-way hull-propeller coupled effect of a fully-actuated AUV

The fully-actuated Autonomous Underwater Vehicle (AUV) has the capability of 6-degree-of-freedom driving, making it suitable for the tasks that require high maneuverability and precise operation. However, there exists a two-way coupled effect between the hull and the thrusters with various arrangements, which has not been clearly and comprehensively understood. This article focuses on the actual thrust of a deployed underwater vehicle, and the impact of operating thrusters on the hull resistance. Through experimental verification and numerical simulation, the actual horizontal and vertical thrusts applied to atypical flat-shaped AUV, and the actual hull resistance, were studied. For the horizontal thrusters, the models describing actual thrust and resistance were established. It indicates a decrease in the thrust and an increase in the resistance during forward motion. For the vertical thrusters, the actual thrust difference between the bow and stern thrusters is relatively small during reverse rotation, but significantly large under the conditions of relative high-speed forward rotation and forward motion. Furthermore, the hull resistance increases significantly when the vertical thrusters are operating, acting on the outer surface of the hull and the thruster channel surface. The availability of the modeling of those coupling effects was validated through the comparisons between dynamics simulation results and actual sailing data. Those studies could provide a reference of practical significance for the structural and control design of underwater vehicles.