Analysis of the Hydrodynamic Performance of a Gate Rudder System

Abstract

Abstract An alternative twin rudder system known as the Gate Rudder© has been applied to newbuild vessels and an existing ship with the aim to improve their hydrodynamic performance and reduce greenhouse gas emissions. The system consists of two asymmetric cross-sections and L-shaped blades located either side of a propeller. The blades generate thrust (duct effect) from the propeller and ship-included flow. Initially, forces and moments of a single blade were measured using a 6-axis strain gauge sensor in the towing tank without a propeller. An alternative measuring device, consisting of a Piezoelectric Macro-Fiber Composite Actuator, was then attached to the blade to investigate flow-induced forces. Finally, Computational Fluid Dynamic (CFD) simulations were compared with the experimental results to identify the source of the oscillating forces. The results show that flow-induced vibrations may occur on the gate rudder blades at both shedding frequencies and the structure’s natural frequency.