Hydrodynamic Force Acting on a Hull in Maneuvering Motion

Abstract

Mathematical models which are constructed from hydrodynamic characteristics of a ship are generally used to simulate maneuvering motion. We calculated the lateral force and yaw moment acting on a hull, which were the main terms in the mathematical model, by a theoretical method, This method was originally proposed by Fuwa, but we simplified his method for practical use. Moreover, we considered the three dimensional effect at the ends and the effect of wave making at the bow. In the calculation method, free vortices were generated at a distance from the keel line. The distance "So" was expressed in terms of the mean draft "d" as follows; S_0=So/d=0.006(Cb・B/d)+0.003 for 40 segments The above empirical equation was determined from the results of eight ships. Further, captive model tests were carried out using the segmented models, and the longitudinal distribution of lateral forces were obtained. After comparison between the experimental results and the calculated ones, the present calculation method was verified.