抄録
Waves generated by ship motions and diffraction when a ship is moving into incident waves cause added resistance of the ship and damping of the motions. No much study, however, has been done so far on those waves particularly with non-zero forward speed of the ship. We present first theoretical wave pattern generated by a pulsating source running with forward speed. This wave pattern was computed with a single integral expression given by Besshos' of the velocity potential of the pulsating and running source. The present authors aware that the velocity potential of a pulsating source thus computed will be usefull to have the 3-D theory of ship motion. Diffraction wave pattern of a ship was computed assuming the ship is slender and the incident waves are of very high frequency. The results were compared with the measured wave pattern. We found that both agree well in the magnitude but the theoretically predicted pattern shifts behind the measured one. The shift is larger as the wave length is larger. Unsteady wave pattern analysis proposed by one of the presemt authors is to measure and analyse diffraction and radiation waves around a ship and to derive added resistance due to waves directly from the measured wave pattern. In order to confirm validity of this analysis, theoretical wave pattern of a ship was analyzed following just the same procedures and approximations as used in the measured wave pattern analysis. We found that the validity of the analysis is complete and we studied the optimum position of the measurement of diffraction and radiation waves to give the most accurate result as well as to be convenient for experiment.
