Numerical Simulations Of The Viscous Flows About Submarines In Maneuvering Motions

Maneuverability is one of the most important sea-going performances of submarine. Although sea-trials/model tests are still the most reliable means in the analysis of submarine maneuvering performance, its short-comings such as long turn-around time, high cost and lack of flow detail information are obvious. With the rapid development of computer technology and numerical methods, CFD has found its way in the analysis of submarine maneuverability by providing an alternative accurate and cost-effective means of simulating real flows. It can be expected that numerical towing tank will turn into reality and trustworthy in near future.This thesis results from a series of numerical simulations performed to investigate the viscous flows about maneuvering submarines and calculate the hydrodynamic forces and moments. The research work is summarized as follows:Firstly, numerical simulations were carried out using different turbulence models to investigate the viscous separation flows about a 6:1 spheroid at incidence, the results are in good agreement with available experimental data and others'computational results.Then, numerical simulations were carried out for the main hull of the SUBOFF submarine with/without sail on top in maneuvering motions. The simulated flow details and computed hydrodynamic forces and moments were compared with experimental data, and were found in good agreement.For the evaluation of the hydrodynamic performance of submarine stern appendages, numerical simulations were done to investigate the viscous flows around a foil, the results are comparable with experimental ones.Finally, numerical simulations were performed to investigate the high Reynolds number, viscous flow field of the SUBOFF and DAPA2 submarine models with full appendages in maneuvering motions, and the hydrodynamic forces and moments acting on them were computed. The results are in good agreement with experimental ones.From the flow simulation practices, it is shown that flow solvers based on RANS equations can be reliably used in the analysis of the hydrodynamic performance of submarine in maneuvering motions, and hopefully can be a alternative cost-effective means in the submarine preliminary design stages.