CFD validation and grid sensitivity studies of full scale ship self propulsion

A comparison between sea trial measurements and full–scale CFD results is presented for two self–propelled ships. Two ships considered in the present study are: a general cargo carrier at Froude number Fn=0.182 and a car carrier at Fn=0.254. For the general cargo carrier, the propeller rotation rate is fixed and the achieved speed and trim are compared to sea trials, while for the car carrier, the propeller rotation rate is adjusted to achieve the 80% MCR. In addition, three grids are used for each ship in order to assess the grid refinement sensitivity. All simulations are performed using the Naval Hydro pack based on foam-extend, a community driven fork of the OpenFOAM software. The results demonstrate the possibility of using high–fidelity numerical methods to directly calculate ship scale flow characteristics, including the effects of free surface, non–linearity, turbulence and the interaction between propeller, hull and the flow field. Keywords: Full scale ship propulsion, Actuator disc, Sea trial validation, Grid sensitivity studies, OpenFOAM