A PARAMETRIC STUDY ON RELATIVE WAVE HEIGHT OF SHIPS IN SHORT CRESTED IRREGULAR SEA WITH FORWARD SPEED

摘要

This paper deals with the parametric study of relative wave heights of ships in short crested irregular seas. Here linear potential theory has been used to describe the fluid motion and 3-D sink-source technique with forward speed has been used to determine hydrodynamic forces for surface ship advancing in waves at constant speed. The time domain simulations of relative wave heights of typical container ship, bulk carrier, pure car carrier (PCC) and general cargo ships in short crested irregular waves have been carried out for three different sea states and for the parametric study of these vessels, different sizes of ships have been considered. Empirical roll damping has been taken into account in time domain analyses of motion responses of sea going ships in rough seas and for ensuring longer time simulation of the random sea waves, unequal frequency spacing has been used. Finally, the numerical results of the maximum and the significant values of irregular relative wave heights are discussed by comparing with some requirements by a classification society of shipping for the different sizes of ships which might provide some important information for the designer of ocean going vessel to assess possible deck load or bottom impact force on future regulation of designing ship.