Numerical Approaches for Submarine Hydrodynamic Design and Performance Analysis

Submarines bring many interesting hydrodynamic challenges that need to be properly addressed to provide precise and reliable information about their performance. Hydrodynamic performance must be evaluated at least in two main operating conditions, namely when it is deeply submerged and at snorkel depth. There are relevant differences in terms of hydrodynamic since the forward speed in the latter condition is typically much lower and of interaction with the free surface. Moreover, submarines used to sail at snorkel depth if they need to accomplish specific tasks, such as communication, that involves the use of surface piercing masts. The proposed study analyses the opportunity provided by different Computational Fluid Dynamic (CFD) approaches to correctly address submarine performance. The resistance in both conditions, masts free surface hydrodynamics and maneuvering behaviors are addressed. Ad-hoc approaches based on in-house developed numerical procedures and open-source software are presented. Different CFD techniques have been used, including Reynolds Averaged Navire Stokes (RANS), Detached Eddy Simulation (DES) and Smoothed Particle Hydrodynamics (SPH), according to the particular physics that need to be studied.