A NUMERICAL STUDY OF ADDED RESISTANCE, SPEED LOSS AND ADDED POWER OF A SURFACE SHIP IN REGULAR HEAD WAVES USING COUPLED URANS AND RIGID-BODY MOTION EQUATIONS

Coupled solutions of two-phase Unsteady Reynolds-Averaged Navier-Stokes equations (URANS) and six degrees-of-freedom (6-DOF) rigid-body motion (RBM) equations are pursued to compute ship's speed loss and added power for a self-propelling ship in regular head sea. A case study is presented fora 1/49 scale model of the ONR Tumblehome (ONRT) (Model 5613) which was tested in the towing tank of the Iowa Institute of Hydraulic Research (IIHR). The computations were carried out for various combinations of towed and self-propelled conditions, and in calm water and regular head waves witha range of wave length and amplitude. The case study demonstrates that the coupled URANS and RBM solution approach can predict added resistance, speed loss and added power of a ship cruising in head waves with commendable accuracy and shed light on the complex interactions among the ship, propeller, waves and flow-fields.