A simplified numerical study of gate rudder propulsion for a twin screw naval ship in open water

The Dynamics of fluid flow in the field of Naval Architecture have continued to challenge hydrodynamicist in analysing complex flow problem around hulls of vessels particularly involving a novel energy saving device such as gate rudder. Various attempts have been made to employ computer based programs with a remarkable success. Therefore, the development of computational methods has been instrumental in making these feat a reality. The use of computer technology lowers the extent of very expensive experimental approaches to estimate the characteristics of ship in the design stage of vessels in the field of Shipbuilding. Hence, hydrodynamicist have employed the help of computational fluid dynamics (CFD) methods to also contributes to the development of experimental methods in the field of Naval Architecture through CFD simulations. The CFD application used in application of gate rudder propulsion system to twin screw naval ship was ANSYS workbench platform. The study began with choosing a suitable naval ship with available benchmark result, hence the choice of DTMB 5415. The bare hull of DTMB was simulated for resistance validation using a multiphase volume of fluid. The turbulence model used for the study was k- ε model. The results showed that it was possible to validate the resistance of a DTMB 5415 bare hull with the model. Also, the open water propeller as well as gate rudder & propeller combination simulation was also adopted in this study so as to evaluate the powering estimate of a GATE rudder system when mounted on a twin screw ship. The result was compared with a bench result of the similar model of a DTMB 5415 fitted with a conventional rudder system. The accuracy of the CFD method used in the study was obtained by comparing it with the current experimental results in the literature. The numerical analyses in the study were performed using the Reynolds Averaged Navier Stokes (RANS) model in the ANSYS Fluent CFD software. Keywords: Naval Ship, Gate Rudder, Propeller, RANS, CFD.