Comparasion betweeen seakeeping short term responses for several input wave spectra, of a lpg carrier 100000 CBM

Abstract

This paper is focused on the seakeeping analysis of a LPG hull ship model, with 238.7 m length. The study includes the linear seakeeping analysis, coupled pitch and heave motions, uncoupled roll motion, in irregular oblique waves, heading angle 0  360 deg., considering the sea described by four power density spectra: ITTC, ISSC, Pierson–Moskowitz and JONSWAP. Based on short term prediction statistical values and specific limits of seakeeping criteria, are obtained the dynamic response statistical polar diagrams, on each motion degree, power density spectrum and cumulative effect, pointing out the influence of the ship speed, heading angle and the difference between the four power density spectra for practical seakeeping assessment. The most restrictive results are obtained in the case using the JONSWAP wave spectrum. The numerical seakeeping analyses are carried out with DYN_OSC program code, in the frame of PhD POSDRU research activities.