Analysis Of Interceptor For Drag Reduction Theory On High Speed Vessel

The stern interceptor is fitted vertically to the transom of the vessel, attaching closely the transom and protruding towards the hull bottom including adjustable and fixed interceptor. The length of stern interceptor is approximately10-3times overall length of the vessel. It is generally known that a well-designed stern interceptor is able to decrease largely resistance and enhance maneuverability by improving the flow field surrounding the vessel and behind the stern. Particularly, the application of the stern interceptor on high-speed craft is proven to be promising. What’s more, it is considered to be of great worth for Green vessels design of Energy Efficiency to research and optimize interceptor performance mechanism.The paper demonstrated systemically related background techniques and foundational theories and analysis approaches. Firstly, we analyzed the resistance characteristics of the square tail vessel and predicted resistance using "Resistance spectrum". And then SOLIDWORKS and HYDROMAX were applied respectively to build three-dimensional vessel model and analyze Hydrostatic performance and stability. Furthermore, the paper described the new features of FLUENT14.0and fundamental knowledge of vessel CFD technology. The commercial software, FLUENT was introduced to simulate the vessel performances, based on implicit unsteady pressure solver in PISO solution. In addition, we applied respectively User-Defined Function (UDF) setting to define boundary condition and Volume of Fluid (VOF) to set free surface of the liquid.The change of buoyancy and trimming moment is considered to play a dominant role on affecting stern interceptor effectiveness through such mechanisms as changing floating condition, influencing the flow field near the stern and thus impacting considerably the vessel resistance. Accordingly, the emphasis on this paper was to not only research characteristics of the vessel resistances with variations of buoyancy and trimming moment, but also analyze the mechanisms of resistance reduction of stern interceptor. First of all, the two-dimensional vessel model was simplified and then calculated numerically its resistance performance under conditions of different velocities and different stern interceptors and different draft depths. In this case, we also performed the change regulations of buoyancy and trimming moment and flow field near the hull with different sizes of stern interceptors. It is these researches that have made contributions to research the hydrodynamic performances of three-dimensional vessel model with stern interceptor.Secondly, this three-dimensional models with and without stern interceptor were calculated in hydrostatical water. We concluded that the improvements of wake flow field were responsible for resistance reduction of stern interceptor. On the other hand, buoyancy difference was calculated. And thus the calculation was undertaken repeatedly after floating condition was modified by HYDROMAX in order to analyze buoyancy effects on resistance reduction due to stern interceptor. Finally, it is proposed that the stern interceptor can modify the excessive trim and improve negotiation posture and develop the work efficiency and maneuverability by analyzing change regulation of angle of tilt without stern interceptor.