Integration of numerical modelling and simulation techniques for the analysis of towing operations of cargo ships

The paper is focused on some benefits gained by the integration of CFD results into the simulation process over time, in order to develop a whole numerical model representing the dynamics of a large merchant ship during towing/escorting operations in severe weather conditions. In particular, the shown application is referred to the simulation of a container ship, towed by two tugboats in a typical Mediterranean harbor. The developed simulator consists of a set of ordinary differential equations, mathematical relationships and numerical tables which represent the ship and the propulsion system dynamics, while CFD method is used in order to model the wind forces, eventually influenced by the presence of some harbor breakwaters, acting on the considered ship. The proposed simulator can be used as a powerful tool to plan safer towing arrangements and procedures, or to analyze in post-processing possible human errors in the case of unfortunate marine accidents.