A METHOD FOR PREDICTING EFFECTS OF PROPELLER-HULL CONFIGURATIONS ON VIBRATORY EXCITATION OF SHIPS

An outstanding problem in naval architecture is the selection of the propeller geometry and the location of the propeller in the aperture in order to reduce the sum of the propeller-induced vibratory bearing forces and moments and the hull surface forces and moments to an acceptable minimum. This paper presents a reliable method for calculating these net excitations for arbitrary stern and propeller configurations. A computer solution for the propeller and hull excitations has been developed and assessed by comparison with two independent sets of model measurments. The paper describes the physical mechanisms involved in visualisation of the velocity field and outlines the mathematical models employed to represent the propeller in the hull wake and the hull surface. Although the method is currently limited to non-cavitating propellers, it can embrace the dominating excitations arising from intermittent blade cavitation. Order from BSRA as No. 54,391.