시간영역 선박운동의 파랑강제력 모델링

Abstract

The ship motion in waves was traditionally classified into seakeeping problem, in which the ship motion is restricted in constant heading and speed, so that the encounter frequency and heading of wave are fixed and the analysis can be done in frequency domain. The need for time-domain ship motion has been growing in order to analyze the ship motion in maneuvering operation and in the phenomenon of stern quatering or following sea, and in larger waves. The linear hydrodynamic modelling in frequency domain can be transformed into the time domain modelling through Fourier transform. However the diffraction force modelling in time domain has many difficult problems in application for arbirtrary heading and speed. In this paper, wave diffraction force modelling that was used by authors since one decade ago was introduced. It used cross drag concept and long wave approximation, and the modelling was for arbitrary heading and speed, and including maneuvering effect. The comparisons with the force measurement results that was done in 24th ITTC intact stability benchmark test. The newly performed model test results were introduced with respect to wave force in time domain.