Hydrodynamic Performance of a Conceptional Seatrain in Heading Wave Based on Small Water Plane Area Trimaran

Abstract Seatrain is a new concept to reduce resistance by using a system that connects multiple ships to achieve broader ocean transportation and ocean warfare. In order to take realistic sea conditions into consideration, the hydrodynamic performance of sea train in heading wave based on multiple identical small-water-plane-area trimarans arranged in a straight line is systematically investigated in present study. Firstly, present numerical method is validated through the comparison of computational and experimental results of a small-water-plane-area-twin-hull in waves, and good agreement can be obtained. Therefore, the resistances, heave and pitch motion of the single trimaran in wave at different speeds from 0.7m/s to 2.8m/s are obtained using STAR-CCM+. Afterward, in order to investigate the interaction of seatrain system, two or three identical trimarans are arranged in a longitudinal column navigating in regular wave. There are two approaches conducted separately, in which trimarans are physical connection or non-connection. The numerical solution is evaluated with two connection approaches and compared with single ships with the same velocity and wave condtion. The result shows that the train composing a very long, slender hull form can increase transportation efficiency and maximum speed by reducing resistance. Meanwhile, the resistance of each hull while operating as a two-ship-train and a three-ship-train is compared with hydrodynamic performance of the single ship. Through the systematic analysis, the characteristics and laws of hydrodynamic interference to minimize the collective resistance of its system are obtained.