Investigations of Hydrodynamic Force Generated on the Rotating Cylinder Implemented as a Bow Rudder on a Large-Scale Ship Model

Abstract

This paper presents experimental studies of the force generated on the rotating cylinder implemented as a bow rudder on a large-scale ship model. The research focused on the maneuverability of the unit equipped with a rotating cylinder (RC) in the front part of the model and its future use as a steering device on small draft river barges. The study presented in this paper is a continuation of the research carried out using the small physical model of a river push train in 1:20 geometric scale equipped with two bow RCs and open water tests of separated rotating cylinders carried out in a flume tank. The experimental test setup with RC installed on the model in 1:24 geometric scale allowed to compare the parameters of standard maneuvers performed with the use of RC and without it. The proposed method based on the measurement of the ship model trajectory during maneuvers allowed to compare the hydrodynamic steering force generated by RC with the steering force generated by the conventional stern spade rudder. The results of the experiments compared with empirical models show a similar trend. RC dynamics was tested for rotational speeds up to 570 RPM (revolutions per minute) and ship model velocity up to 1 m/s. The rotating cylinder generated velocity field is presented and phenomena influencing the generated hydrodynamic force are discussed.

Wind-Assisted Ship Propulsion: Matching Flettner Rotors with Diesel Engines and Controllable Pitch Propellers

“…Flettner rotors are rotating cylinders (usually spun by an electric motor) that generate aerodynamic lift and drag when immersed in a fluid stream; the working principle belongs to the so-called Magnus effect [2]. In the case of wind-assisted ship propulsion, the fluid considered is air; however, there are also ship applications of the Magnus effect in water; an example is reported in [3], where a rotating cylinder acts as a bow steering system that improves vessel manoeuvrability, turning, and course keeping ability. The experimental setup and the measurements of the hydrodynamic forces generated on the rotating cylinder (rotor) under uniform water flow, including the free surface effect, have been presented in [4].…”