Study on the design procedure of rudder attached thrust fin for merchant ship based on computational fluid dynamics

Abstract

Rudder added thrust fins have gained popularity as an energy saving device (ESD) by virtue of; simple design, easy installation and its effectiveness. The current work seeks to investigate the influence of geometric parameters and mounting orientation on the energy saving effect of rudder attached thrust fins based on numerical analysis. Open water, bare hull resistance and self-propulsion simulations were carried out by solving the Reynolds-Averaged-Navier-Stokes Equations (RANSE) using a Computational fluid Dynamics (CFD) code. In the case of geometrical parameters, hydrofoil camber and fin span were varied. The fin orientation was then studied by varying the mounting direction in relation to the angle of attack and the location of pressure and suction sides. A validation study carried out showed good agreement between CFD and model tests. It was noted that the rudder thrust fin is sensitive to the hydrofoil orientation. Also, with the right hydrofoil orientation, the fin performance is optimum at an angle of attack of about 2°. This study presents a design guideline for rudder thrust fins to ensure optimum energy gains.