A comprehensive analysis of a numerical self-propulsion procedure for high-speed marine vehicles

Abstract

In the context of numerical self-propulsion predictions, the literature on high-speed marine vehicles (HSMV) is still relatively scarce. Actually, extensive numerical analyses are rarely considered for these applications because of the not-so-stringent design constraints and contract requirements concerning these crafts and also thanks to the advantages of series production. On the contrary, with the growth of the market requests, in particular, in the direction of Greenhouse Gas Reduction, the exact knowledge of the vessel working point, in terms of speed and engine configuration, pushes the researchers to investigate all the factors which deeply define the propulsion condition. In the present paper, two existing vessels have been numerically studied using a robust and industrially affordable procedure based on some simplified viscous Computational Fluid Dynamic approaches to predict the self-propulsion working points. The obtained results have been then compared with available sea trials showing a very high agreement even if some uncertainties in both the experimental measurements and the CFD results still exist. The impact of these uncertainties has been further investigated to assess the reliability of the self-propulsion prediction, showing that the maximum speed can be obtained with an uncertainty of about 1 knot and 10% of the corresponding engine load. A more robust prediction can be obtained by including the uncertainty assessment in the propulsion analyses. The validity of the proposed analyses is further supported because the numerical uncertainty falls inside the uncertainty obtained from the available full-scale measurements, so defining a more robust prediction of the vessel propulsion point for design purposes.