Numerical simulation of the free-running of a ship using the propeller model and dynamic overset grid method

ABSTRACT An unsteady Reynolds averaged Navier-Stokes (URANS) solver to estimate the trajectory on the free-running condition of a conventional ship is developed. Ship motions are obtained by solving the motion equations and accounted for by the moving grid technique. Propeller effects are accounted for by the body forces that are derived from the propeller model, which is based on the potential theory. The prescribed rudder motions of typical free-running conditions are accounted for using the dynamic overset grid method, in which the overset information is updated at each temporal step by implementing the existing overset grid method as the numerical library. The flow around the ship hull during the turning motions is analysed, and strong interactions between the ship hull and rudder in the propeller accelerated flows are observed. Through comparisons, the present method shows its applicability to compute the flow around a ship in free-running motion.