Underwater vehicle manoeuvring: integration of CFD in the design process

Abstract

The design of ship external shape, consistent with both architectural constraints and manoeuvring performances requirements, is crucial for the submarine projects at Naval Group. The deployment of numerical methods for hydrodynamics represented a revolution in the historical design process. For several years, these methods are systematically applied to new projects of submarines and underwater vehicles.Although numerical simulation has already been used for several decades in submarine design, Naval Group is investing on these new calculation methods for almost 10 years. By their mean, main performances of the submerged submarine like dynamic stability, turning diameter, trim change capability, forces coefficients for elementary motions (forward speed with drift/incidence, rudder angle…) and appendage hydrodynamic loading become predictable.These methods are validated by comparison with the accumulated knowledge on the different submarine designed, built and sea-proven by Naval Group during the last five decades. The turning performance is thus compared to the results from sea trials of the studied submarines. The efforts on the submarine and the hydrodynamic loads applied to the rudders during elementary manoeuvres are compared to model tests measurements. This comparison on an extensive database enabled to validate the deployed methods, and to quantify the inherent uncertainty.