Lagrangian modeling and simulation of the free surface-affected dynamics of underwater vehicles

The paper deals with the development of a novel simulator for underwater vehicles that takes into account the interaction between the submerged body and the free water surface. By using a Lagrangian approach, the potential flow theory is combined with the 6-DoF equations of motions, in order to derive a mathematical model of the system dynamics to be solved in time-domain. A numerical model is then specifically developed and an extensive simulation campaign is carried out, leading to the Submerged Bodies Simulator (SubBoS). The results highlight an extension of the prediction validity with respect to the state-of-art modeling, typically based on stringent hypotheses on body motion (e.g. small displacements, pure surge motion).