A time-efficient CFD approach for hydrodynamic coefficient determination and model simplification of submarine

Maneuverability is one of the most important performance characteristics of submarines. Hydrodynamic model is increasingly relied on as a design approach to determine the inherent motion behavior of a proposed submarine before construction. Standard submarine motion equations are the most used hydrodynamic model, in which more than 100 coefficients need to be estimated. These coefficients have to be determined by captive model tests, semi-empirical method and potential flow method on the basis of existing approach. The separately determining approach makes it difficult to assess model reliability. This paper proposes a time-efficient approach for the estimation of hydrodynamic coefficients using computational fluid dynamics (CFD) method. Instead of a repetitive and time-consuming process, the proposed spatial captive motion could provide all necessary information for determination of all required coefficients in only one simulation. Linear regression, based on the least square method, is employed to determine coefficients in hydrodynamic model. Statistical investigation, correlation and significance analysis, indicates that the standard submarine motion equations can be further simplified when submarine moving forward with small perturbations along other directions. The final simplified motion equations have much fewer components than the original model while fitting accuracy remained. Validation results prove that spatial captive motion simulation and the simplification approach employed in this paper are effective and reliable. It should have a large scope in further maneuverability research.