肥大船の進路安定性と流体力に関する実験的研究

抄録

It is an important problem to estimate the course stability of full-bodied, e.g., large tankers. Although model experiments are usefull for this purpose, a difficulty comes from the fact that some models have unusually good stability on course which may or may not correspond to the full-size behavior. At the same time rather a fickle behavior on course is often experienced. In this paper such unusually stable phenomenon and its possible cause are discussed and the concerning hydrodynamic forces were measured for the two typical models of 4.5 meter long ; one is unstable model and another unusually stable one, both having the same principal dimensions. The hydrodynamic derivatives obtained from the measured forces are compatible with the course stability observed at the free sailing model tests. Differences between the hydrodynamic derivatives of the two models are seen for Y_β', N_β', Y_r', N_r' and the cause is supposed by the differences on the aft-framelines and stern profile. The difference is not seen on the rudder force, but seen on the aft-body force. The propeller revolution affects remarkably to the hydrodynamic forces on the aft-body and seems to play an important role on the above mentioned unusual stability on course.