Numerical prediction for vertical dynamic anti-sinking performance of underwater vehicle

Abstract

Computational fluid dynamics (CFD) simulations of an underwater vehicle (UV) during self-propulsion and dynamic anti-sinking maneuvers are presented. A generic submarine, Joubert BB2, was selected as the test model, which was modified by the Maritime Research Institute, Netherlands (MARIN). Different recovery maneuvers for improving the anti-sinking ability were performed when the UV bow cabin was broken. The overset mesh method was used to simulate the deflection of the rudder and stern planes, and a body-force propeller represented by an actuator disk incorporating predetermined propulsion properties provided the thrust and torque for self-propulsion. Extra vector forces of inflow water forces and recovery buoyancy forces were proposed to simulate the flooding of a bow cabin and recover buoyancy by emptying the ballast. Numerical simulations were performed for 20 different combinations of vertical anti-sinking maneuvers, including stern control surfaces, increasing ship speed, and emptying the ballast water. The pitch angle and depth characteristics of UV self-propelled motion were analyzed based on the pre-set anti-sinking criterions. The results indicated stern control surfaces combined with accelerating could effectively maintain the UV's depth and pitch angle, and discharge ballast water could always make it surface quickly. We hope that this study will provide ideas for further research on anti-sinking abilities.