Preliminary Self-propulsion Simulations of a Displacement Hull with Different Propulsion Arrangements

This work is part of a broader national research project aimed at developing a small-scale vessel prototype fuelled by a methanol fuel cell. The prototype hull model will be part of a systematic series of hulls. The Series is characterized by low-resistance hull forms which could be used as a reference for the design of zero-emission passenger craft and small ships, for operations in urban and coastal waters, as well as in Emission Control Areas. In particular, the paper focuses on the hydrodynamic analysis of the parent hull, and the reported results will provide the basis for the development of the Systematic Series. The analysis includes the prediction of the calm water resistance for the bare hull and with appendages at the Fr (Froude Number) range of 0.2 to 0.41, and the results of the self-propulsion analysis computed at Fr 0.32 and F 0.41. Additionally, self-propulsion analyses were carried out considering both single-screw and twin-screw arrangements to estimate the propulsive factors and compare the overall efficiency. The analysis has been carried out by means of Computational Fluid Dynamics (CFD) in model scale. Further insights have been provided on the comparisons of the nominal wake field, to highlights the differences among the two proposed arrangements. The Self-propulsion simulations have been computed using the actuator disk approach. The hull running attitude has been predicted using a dynamic overset grid.