Estimation method for life-cycle fuel consumption of merchant ships

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In recent years, the importance has been recognizing for the rigorous predictions of life-cycle (LC) fuel consumption of ships to evaluate the life-cycle value (LCV) of ships. From a ship design point of view, it is of crucial importance to establish reliable methods for the accurate prediction of ship performance in the realistic wave environment as a design analysis tool. To achieve this objective, a new prediction procedure based on CFD ship motion simulation is developed for predicting ship performance in a seaway in the present study. This has been intended for the establishment of the evaluation method of LC fuel consumption.Two versions of the CFD ship-motion simulation code named WISDAM-X and WISDAM-XI are described with a number of application examples. Since the non-linear free-surface and body-surface conditions are satisfied exactly on the moving ship body surface in the framework of overlapping grid system (WISDAM-X) or multi-block grid system (WISDAM-XI), both codes cope with arbitrary ship motions in arbitrary wave conditions. The WISDAM-X code is especially used for the design of conventional type ships. The simulation results demonstrate that the computed pressure on the surface of the bow-part shows fairly good agreement with the measured data in a wide range of wave conditions. The simulations of the cases in the oblique waves elucidate the formation of unsteady free-surface- shock-wave which plays an important role for the added resistance. The WISDAM-XI code is used for the prediction of hydrodynamic performance of multihull vessels. Resistance and seakeeping performance of monohull, catamaran and trimaran vessels is estimated by the CFD code and they are validated through comparison with experiments.