Propellers/Shafting 2006 Symposium, 12-13 September, 2006, Williamsburg, Virginia
This paper presents the results of an experimental study on the effects of propeller hub angle and azimuth conditions on the propulsive characteristics of puller podded propulsors in open water conditions. The propulsive performance of two model puller-podded units with different hub geometry was measured using a custom designed pod dynamometer in a towing tank. The podded units were tested to measure the thrust and torque of the propeller and the forces on the whole unit in three orthogonal directions. The tests were conducted for a range of advance coefficients from 0 to 1.2, combined with the range of static azimuth angles from +20° to -20° with a 10° increment. The dynamometer system consisted of a six-component global dynamometer and a three-component pod dynamometer. The variation in the propulsive performance due to the changes in hub geometry was examined first, followed by a study on the effect of azimuth conditions on the forces and moments on the propulsor. The force and moment measurements are presented as functions of advance coefficient and azimuth angle. The results showed that for the range of azimuth angles tested, the thrust and torque of the propeller and the forces on the whole unit in three orthogonal directions are functions of the azimuth angle for puller propulsors.