Abstract
This paper investigates experimentally and numerically the effect on the propeller shaft loads of dynamically changing propeller speed and azimuth angle of thruster propellers. Model tests with a six-component shaft dynamometer were performed in the large towing tank at the Marine Technology Centre. A blade element momentum theory (BEMT) model is applied for numerical analysis.
It is found that the side forces and bending moments on the propeller in strongly oblique inflow are quite sensitive to dynamically changing azimuth angle; for instance are the maximum values of vertical side force and horizontal bending moments effectively doubled when the azimuth angle is changed dynamically. On the other hand, dynamically changing the azimuth angle is less important for the thrust and torque of the propeller. For ships, the effect of dynamically changing the propeller speed can be ignored and the quasi-static values used.