Turning ability characteristics study of a twin screw vessel by CFD

The turning circle manoeuvre of a self-propelled tanker like ship model is numerically simulated through the integration of the Unsteady Reynolds Averaged Navier-Stokes (URANS) equations coupled with the equations of the motion of a rigid body. The solution is achieved by means of the unsteady RANS solver Xnavis developed at CNR-INSEAN. The ship model is in its fully appended configuration, and it is characterized by the presence of two propellers and one rudder. Each propeller is taken into account by a model based on the actuator disk concept. It is shown that, in order to accurately predict the trajectory, the side force developed by the propeller should be taken into account; several models are tested. Comparison with experimental data from free running tests is provided. The main features of the flow field, with particular attention to the vortical structures detached for the hull is presented as well.