PARAMETRIC DESIGN AND OPTIMIZATION OF A PIVOTING S-TYPE RUDDER FOR CONTAINERSHIPS

摘要

This study proposes an energy-saving S-type rudder design to deal with the inhomogeneous inflow from a rotating propeller behind a containership. The S-type rudder was modelled parametrically using four-digit NACA foils as section profiles together with Non-uniform rational B-splines (NURBS) surface formulations. A three-stage optimization process is proposed to reduce the number of design iterations necessary to achieve an optimal design. The propulsion simulations were done via CFD software, which solves the hydrodynamics of viscous flow, as governed by the Reynold-averaged Navier-Stokes (RAN S) equations. Validations were performed with experimental model tests, including hull resistance, propeller open-water performance, and propulsion in calm water. Finally, energy recovery for different operational conditions is controlled by an innovative pivoting mechanism. The results show that the optimized S-type rudder can reduce delivered horsepower by 1% to 3%.