Performance characteristics of static and dynamic azimuthing podded propulsor

Abstract

This paper presents results and analyses of an experimental study into the effects of static and dynamic azimuthing conditions on the propulsive characteristics of a puller podded unit in open water. The model propulsor was instrumented to measure thrust and torque of the propeller, three orthogonal forces and moments on the unit, rotational speed of the propeller, azimuthing angle and azimuthing rate. The model was first tested over a range of advance coefficients at various static azimuthing angles in the range of 0\ub0 to 360\ub0. These tests were followed by tests in which the azimuthing angle was varied dynamically at different azimuthing rates and propeller rotational speeds. The performance coefficients of the propeller and the pod unit showed a strong dependence on the propeller loading and azimuthing angle. The open water characteristics were mostly irregular for the astern thrust conditions in the azimuthing angle beyond the range 90\ub0 to 270\ub0, where the flow separation at the propeller blades and the pod-strut body might have occurred. The coefficients in static azimuthing conditions fit well with a 10th order polynomial fit of the data obtained in the dynamic azimuthing condition in the corresponding azimuthing angles and advance coefficients. An uncertainty analysis of the measurements is also presented.Peer reviewed: NoNRC publication: Ye